Plant extract compositions and methods of preparation thereof

ABSTRACT

Embodiments described herein relate generally to plant extract compositions and methods to isolate cutin-derived monomers, oligomers, and mixtures thereof for application in agricultural coating formulations, and in particular, to methods of preparing plant extract compositions that include functionalized and non-functionalized fatty acids and fatty esters (as well as their oligomers and mixtures thereof), which are substantially free from accompanying plant-derived compounds (e.g., proteins, polysaccharides, phenols, lignans, aromatic acids, terpenoids, flavonoids, carotenoids, alkaloids, alcohols, alkanes, and aldehydes) and can be used in agricultural coating formulations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/684,140, filed Nov. 14, 2019, which is a continuation of U.S. patentapplication Ser. No. 15/660,260, filed Jul. 26, 2017, which is acontinuation of U.S. patent application Ser. No. 15/254,263, filed Sep.1, 2016, which issued as U.S. Pat. No. 9,743,679, which is acontinuation of International Application PCT/US2016/033617, filed May20, 2016, which claims the benefit of U.S. Provisional PatentApplication No. 62/164,312, entitled “Plant Extract Compositions andMethods of Preparation Thereof,” filed May 20, 2015, the disclosures ofwhich are hereby incorporated by reference in their entirety.

BACKGROUND

The present disclosure relates to plant extract compositions, and tomethods of forming the same. Common agricultural products aresusceptible to degradation and decomposition (i.e., spoilage) whenexposed to the environment. Such agricultural products can include, forexample, eggs, fruits, vegetables, produce, seeds, nuts, flowers, and/orwhole plants (including their processed and semi-processed forms).Non-agricultural products (e.g., vitamins, candy, etc.) are alsovulnerable to degradation when exposed to the ambient environment. Thedegradation of the agricultural products can occur via abiotic means asa result of evaporative moisture loss from an external surface of theagricultural products to the atmosphere and/or oxidation by oxygen thatdiffuses into the agricultural products from the environment and/ormechanical damage to the surface and/or light-induced degradation (i.e.,photodegradation). Furthermore, biotic stressors such as, for example,bacteria, fungi, viruses, and/or pests can also infest and decompose theagricultural products.

Conventional approaches to preventing degradation, maintaining quality,and increasing the life of agricultural products include refrigerationand/or special packaging. Refrigeration requires capital-intensiveequipment, demands constant energy expenditure, can cause damage orquality loss to the product if not carefully controlled, must beactively managed, and its benefits are lost upon interruption of atemperature-controlled supply chain. Special packaging can also requireexpensive equipment, consume packaging material, increase transportationcosts, and require active management. Despite the benefits that can beafforded by refrigeration and special packaging, the handling andtransportation of the agricultural products can cause surface abrasionor bruising that is aesthetically displeasing to the consumer and servesas points of ingress for bacteria and fungi. Moreover, the expensesassociated with such approaches can add to the cost of the agriculturalproduct.

The cells that form the aerial surface of most plants (such as higherplants) include an outer envelope or cuticle, which provides varyingdegrees of protection against water loss, oxidation, mechanical damage,photodegradation, and/or biotic stressors, depending upon the plantspecies and the plant organ (e.g., fruit, seeds, bark, flowers, leaves,stems, etc.). Cutin, which is a biopolyester derived from cellularlipids, forms the major structural component of the cuticle and servesto provide protection to the plant against environmental stressors (bothabiotic and biotic). The thickness, density, as well as the compositionof the cutin (i.e., the different types of monomers that form the cutinand their relative proportions) can vary by plant species, by plantorgan within the same or different plant species, and by stage of plantmaturity. The cutin-containing portion of the plant can also containadditional compounds (e.g., epicuticular waxes, phenolics, antioxidants,colored compounds, proteins, polysaccharides, etc.). This variation inthe cutin composition as well as the thickness and density of the cutinlayer between plant species and/or plant organs and/or a given plant atdifferent stages of maturation can lead to varying degrees of resistancebetween plant species or plant organs to attack by environmentalstressors (i.e., water loss, oxidation, mechanical injury, and light)and/or biotic stressors (e.g., fungi, bacteria, viruses, insects, etc.).

SUMMARY

Embodiments described herein relate generally to plant extractcompositions and methods to isolate cutin-derived monomers, oligomers,and mixtures thereof for application in agricultural coatingformulations, and in particular, to methods of preparing plant extractcompositions that include functionalized and non-functionalized fattyacids and fatty esters (as well as their oligomers and mixturesthereof), which are substantially free from accompanying plant-derivedcompounds (e.g., proteins, polysaccharides, phenols, lignans, aromaticacids, terpenoids, flavonoids, carotenoids, alkaloids, alcohols,alkanes, and aldehydes) and can be used in agricultural coatingformulations.

In some embodiments, a method for preparing a plant extract compositionincludes thermally and/or mechanically and/or enzymatically and/orchemically treating the plant matter to at least partially separate acutin-containing portion from the plant matter. In some embodiments, theplant matter is subjected to elevated temperature and/or pressure in anaqueous medium (e.g., as in pressure cooking) to partially separate acutin-containing portion from the plant matter. Alternatively, the plantmatter may be subjected to lower temperatures (e.g., as in freezing) topartially separate a cutin-containing portion from the plant matter. Insome embodiments, the plant matter is subjected to sonication in anaqueous medium to partially separate a cutin-containing portion from theplant matter. Optionally, the cutin-containing portion is heated in amixture of ammonium oxalate and oxalic acid to aid separation of thecutin from the non-cutin-containing portion (i.e., the remainder of thecuticle and unwanted plant matter). Optionally, this separation can beachieved (or assisted) enzymatically using enzymes capable ofhydrolyzing ester bonds and/or alternatively using enzymes capable ofbreaking down polysaccharides that comprise the non-cutin-containingportion of the plant. Optionally, the cutin-containing portion isrefluxed in at least one organic solvent (such as chloroform and/ormethanol) to remove residual waxes and/or any remaining soluble polarcomponents from the cutin. Alternatively, removal of residual waxes andremaining soluble components can be achieved using supercritical CO₂ orsupercritical H₂O. The cutin is then refluxed in a solvent having a highpH (e.g., in the range of about 10 to 14, and typically in the range of12 to 14), for example a solvent in which metal alkoxide or metalhydroxide (or alternative source of alkoxide or hydroxide) is dissolved,to at least partially depolymerize the cutin and obtain an intermediateextract including a plurality of esterified or fatty acid cutinmonomers, their oligomers, or mixtures thereof. In cases where theintermediate extract is obtained from (metal) alkoxide-mediateddepolymerization, the pH of the intermediate extract is then adjusted tobe in the range of about 6.5 to 9.0. In cases where the intermediateextract obtained from (metal) hydroxide-mediated depolymerization, thepH of the intermediate extract is then adjusted to be in the range ofabout 1.0 to 6.0. Alternatively, the cutin can be at least partiallydepolymerized under acidic conditions to obtain an intermediate extractincluding a plurality of fatty acid cutin monomers, oligomers, ormixtures thereof. The intermediate extract is then precipitated and/orextracted and purified (such as by washing with one or more selectivesolvents) to obtain the plant extract such that the plant extract issubstantially free from accompanying plant-derived compounds (e.g.,proteins, polysaccharides, phenols, lignans, aromatic acids, terpenoids,flavonoids, carotenoids, alkaloids, alcohols, alkanes, and aldehydes).Further purification by chromatography or recrystallization in aselective solvent may also be carried out after washing to obtain thefinal extract.

In some embodiments, a method for preparing a plant extract compositionincludes obtaining cutin from a cutin-containing portion of a plantmatter, the cutin-containing portion being at least partially separatedfrom a non-cutin-containing portion of the plant matter, and at leastpartially depolymerizing the cutin in a first solvent to obtain a firstsolution comprising a first intermediate extract dissolved in the firstsolvent, wherein the first solution has a pH in the range of 10 to 14,and the first intermediate extract includes a plurality of cutin-derivedmonomers, oligomers, or combinations thereof. The method furtherincludes evaporating at least a portion of the first solvent, causingthe first intermediate extract to solidify, dissolving the solidifiedfirst intermediate extract in a polar solvent to obtain a secondsolution, and acidifying the second solution, causing the firstintermediate extract to resolidify.

In some embodiments, a method for preparing a plant extract compositionincludes obtaining cutin from a cutin-containing portion of a plantmatter, the cutin-containing portion being at least partially separatedfrom a non-cutin-containing portion of the plant matter, and at leastpartially depolymerizing the cutin in a first solvent to obtain a firstsolution comprising a first intermediate extract dissolved in the firstsolvent, wherein the first intermediate extract includes a plurality ofcutin-derived monomers, oligomers, or combinations thereof. The methodfurther includes acidifying the first intermediate extract, selectivelyfiltering the first intermediate extract to obtain a second intermediateextract having a higher purity than the first intermediate extract, anddissolving the second intermediate extract in a second solvent to obtainthe plant extract composition.

In some embodiments, a method for preparing a plant extract compositionincludes obtaining cutin from a cutin-containing portion of a plantmatter, the cutin-containing portion being at least partially separatedfrom a non-cutin-containing portion of the plant matter, and at leastpartially depolymerizing the cutin in a first solvent to obtain a firstsolution comprising a first intermediate extract dissolved in the firstsolvent, wherein the first solution has a pH in the range of 10 to 14,and the first intermediate extract includes a plurality of cutin-derivedmonomers, oligomers, or combinations thereof. The method furtherincludes evaporating at least 25% of a volume of the first solvent fromthe solution, adding a polar solvent to the first solution to obtain asecond solution, and acidifying the second solution, causing the firstintermediate extract to precipitate.

In some embodiments, a method for preparing a plant extract compositionincludes obtaining cutin from a cutin-containing portion of a plantmatter, the cutin-containing portion being at least partially separatedfrom a non-cutin-containing portion of the plant matter, and exposingthe compound to supercritical carbon dioxide to selectively reduce aconcentration of at least one of proteins, polysaccharides, phenols,lignans, aromatic acids, terpenoids, flavonoids, carotenoids, alkaloids,alcohols, alkanes, aldehydes, and waxes. The method further includes atleast partially depolymerizing the cutin in a first solvent to obtain afirst solution comprising a first intermediate extract dissolved in thefirst solvent, wherein the first solution has a pH in the range of 10 to14, and the first intermediate extract includes a plurality ofcutin-derived monomers, oligomers, or combinations thereof. The methodalso includes acidifying the first intermediate extract and obtainingthe plant extract composition, wherein the plant extract compositioncomprises a second solution comprising the monomers, oligomers, orcombinations thereof dissolved in a second solvent.

In some embodiments, a method for preparing a plant extract compositionincludes obtaining cutin from a cutin-containing portion of a plantmatter, the cutin-containing portion being at least partially separatedfrom a non-cutin-containing portion of the plant matter, and at leastpartially depolymerizing the cutin in a first solvent having a pH in therange of 10 to 14 to obtain a first solution comprising a firstintermediate extract dissolved in the first solvent, wherein the firstintermediate extract includes a plurality of cutin-derived monomers,oligomers, or combinations thereof. The method further includesacidifying the first solution, selectively filtering the first solutionto remove impurity constituents, at least partially evaporating thefirst solvent to cause the first intermediate extract to solidify, anddissolving the first intermediate extract in a second solvent.

In some embodiments, a method of preparing a plant extract compositionincludes obtaining cutin from a cutin-containing portion of a plantmatter, the cutin-containing portion being at least partially separatedfrom a non-cutin-containing portion of the plant matter and at leastpartially depolymerizing the cutin in a first solvent to obtain a firstsolution comprising a first intermediate extract in the first solvent,the first intermediate extract including a plurality of cutin-derivedmonomers, oligomers, or combinations thereof. The method furtherincludes selectively filtering the first intermediate extract to obtaina second intermediate extract having a higher purity than the firstintermediate extract, the second intermediate extract including at leastone of the cutin-derived monomers, oligomers, or combinations thereof,and functionalizing the cutin-derived monomers, oligomers, orcombinations thereof of the second intermediate extract to form theplant extract composition.

In some embodiments, a method of protecting an agricultural product frombiotic stress includes obtaining a plant extract composition comprisinga plurality of cutin-derived monomers, oligomers, or combinationsthereof, functionalizing the cutin-derived monomers, oligomers, orcombinations thereof by esterifying the cutin-derived monomers,oligomers, or combinations thereof with a glycerol molecule, and causingthe agricultural product to be coated with the functionalizedcutin-derived monomers, oligomers, or combinations thereof.

In some embodiments, a method of prolonging the life of an agriculturalproduct includes obtaining a plant extract comprising a plurality ofcutin-derived monomers, oligomers, or combinations thereof,functionalizing the cutin-derived monomers, oligomers, or combinationsthereof by esterifying the cutin-derived monomers, oligomers, orcombinations thereof with a glycerol molecule, and causing theagricultural product to be coated with the functionalized cutin-derivedmonomers, oligomers, or combinations thereof.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic flow diagram of an exemplary method for preparinga plant extract composition, according to an embodiment.

FIG. 2 shows high resolution time lapse photographs of lemons, both withand without coatings formed of compounds described herein.

FIG. 3 is a normalized plot of the cross-sectional areas of the lemonscoated with and without compounds described herein as a function oftime.

FIG. 4 shows high resolution time lapse photographs of strawberries,both with and without coatings formed of compounds described herein.

FIG. 5 is a plot of the percent mass loss of blueberries with andwithout coatings formed of the compounds described herein as a functionof time.

FIG. 6 shows high resolution photographs of blueberries, both with andwithout coatings formed of compounds described herein after five days.

FIG. 7 shows plots of purity data of an extract composition describedherein.

FIG. 8 is an elemental analysis of an extract composition describedherein.

FIG. 9 shows high resolution photographs of uncoated key limes.

FIG. 10 shows high resolution photographs of key limes coated withcompounds of a first extract.

FIG. 11 shows high resolution photographs of key limes coated withcompounds of a second extract.

DETAILED DESCRIPTION

The biopolyester cutin forms the main structural component of thecuticle that composes the aerial surface of most land plants and plays asignificant role in providing plants a protective barrier against bothabiotic and biotic stressors. The thickness, density, as well as thecomposition of the cutin (i.e., the different types of monomers thatform the cutin and their relative proportions) can vary by plantspecies, by plant organ within the same or different plant species, andby stage of plant maturity. These variations can define the amount,degree, or quality of protection (and degree of plasticity) offered bythe cutin layer to the plant or plant organ against environmental and/orbiotic stressors. Cutin is formed from a mixture of polymerized mono-and/or polyhydroxy fatty acids and embedded cuticular waxes. Among thehydroxy fatty acids, polyhydroxy fatty acids (e.g., dihydroxy fattyacids or trihydroxy fatty acids), once esterified, can form tightlybound networks with high crosslink density and lower permeability ascompared to monohydroxy fatty acids and can thereby provide betterprotection against environmental stressors.

Embodiments described herein relate generally to plant extractcompositions and, in particular, to methods of preparing plant extractcompositions that include hydroxy fatty acids and hydroxy fatty esters(as well as their oligomers and mixtures thereof), which aresubstantially free from accompanying plant-derived compounds (e.g.,proteins, polysaccharides, phenols, lignans, aromatic acids, terpenoids,flavonoids, carotenoids, alkaloids, alcohols, alkanes, and aldehydes)and can be used in agricultural coating formulations. Specifically,plant extract compositions described herein that are formed from plantmatter can subsequently be applied to other plant or agriculturalproducts in order to form a protective coating over the products, or toenhance or modify existing coatings (either naturally occurring ordeposited coatings) which are on the outer surface of the products. Theapplied coatings can, for example, serve to protect the products frombiotic stressors such as bacteria, fungi, viruses, and/or pests. Theapplied coatings can also (or alternatively) serve to increase the shelflife of produce without refrigeration, and/or to control the rate ofripening of produce.

In some embodiments, in order to achieve one or more of the benefitsdescribed above for applications in which an agricultural coating issubsequently formed from a plant extract composition derived from plantmatter, it may be necessary for the plant extract composition to behighly purified, e.g., to include the monomer and/or oligomer units thatform the structural building blocks of the coatings and tosimultaneously be substantially free of other accompanying plant-derivedcompounds such as proteins, polysaccharides, phenols, lignans, aromaticacids, terpenoids, flavonoids, carotenoids, alkaloids, alcohols,alkanes, and aldehydes. In particular, plant extracts to be used inagricultural coating applications typically need a substantially higherlevel of purity than when extracted for other applications (e.g.,characterization of plant matter). In some cases, achieving the requiredlevel of purity requires a number of additional steps that may not beadvantageous or desirable in other applications.

The plant extract compositions described herein can be derived orobtained in a number of ways. For example, in some embodiments thecompositions are derived directly from a cutin-containing portion ofplant matter, such as by depolymerizing (or at least partiallydepolymerizing) the cutin to obtain a plurality of cutin-derivedmonomers, oligomers, or combinations thereof, and optionallyfunctionalizing (e.g., modifying) the cutin-derived monomers oroligomers. Alternatively, in other embodiments the plant extractcompositions are obtained by decomposition of palm oil, and optionallysubsequently functionalizing (e.g., modifying) the monomers or oligomersobtained by the palm oil decomposition. In still other embodiments, theplant extract compositions are obtained from commercial sources, forexample by purchasing monomers, oligomers, or combinations thereof whichwere derived or formed by one of the methods described above, or byother methods.

As described above, the compositions of the present disclosure can bederived or obtained from commercial sources. For instance, compositionscan be made by functionalizing a commercially available fatty acid(e.g., palmitic acid or 10, 16-dihydroxyhexadecanoic acid). The fattyacids thus obtained can be functionalized to improve their properties ascoatings for agricultural products. For example, in some embodiments, afatty acid (e.g., a commercially available fatty acid or a fatty acidextracted from plant cutin) is esterified. The esterification can becompleted directly via the reaction of the free carboxylic acid with anappropriate alcohol. Alternatively, the esterification can be completedby transesterification of a fatty acid ester (e.g., methyl palmitate)with an appropriate alcohol.

In some embodiments, the cutin-derived monomers, oligomers, orcombinations thereof (e.g., the fatty acid compositions) of the presentdisclosure are functionalized to their corresponding glycerol esters(e.g., 1-glycerol or 2-glycerol esters). That is, a fatty acid of thepresent disclosure (e.g., palmitic acid) can be esterified usingglycerol or a derivative thereof to give a fatty acid ester of glycerol(e.g., 1,3-dihydroxypropan-2-yl palmitate or 2,3-dihydroxypropylpalmitate).

As set forth in the present disclosure, functionalized fatty acids(e.g., fatty acid-glycerol esters) can have advantageous properties thathelp to preserve agricultural produce when applied to the surface of theproduce (e.g., can prolong the shelf life of agricultural produce). Insome embodiments, substantially all of the fatty acids in thecompositions described herein are esterified with a glycerol molecule.For instance, both commercially derived fatty acids as well as fattyacids extracted from plant compositions can be functionalized as aglycerol ester.

In some embodiments, the monomer and/or oligomer units of the plantextract compositions described herein can be applied to the surface ofan agricultural product that does not naturally produce the monomerand/or oligomer units. For instance, the monomer and/or oligomer unitscan comprise a plurality of fatty acids that can be commerciallyavailable or extracted from plant matter. These compositions can beapplied to agricultural products that do not naturally produce, forinstance, the same types of fatty acids. In one example, a compositionof monomers and/or oligomers derived from palmitic acid can be appliedto an agricultural product that does not naturally produce palmiticacid.

Additionally, in some embodiments, the monomer and/or oligomers units ofthe compositions described herein can be functionalized and applied toagricultural products that do not naturally produce suchfunctionalization. For instance, a glycerol-ester of a fatty acid (e.g.,1,3-dihydroxypropan-2-yl palmitate or 2,3-dihydroxypropyl palmitate or acombination thereof) can be applied to the surface of an agriculturalproduct that does not naturally produce glycerol-functionalized fattyacids.

In some embodiments, the addition of non-naturally occurring (e.g.,functionalized) monomer and/or oligomer units of the plant extract(e.g., fatty acids) can have beneficial properties when applied toproduce to form a coating. For instance, the coatings can reducemoisture loss from the produce and/or reduce microbial growth on thesurface of the produce.

In some embodiments, the monomer and/or oligomer units of the plantextract compositions are obtained from cutin found in plant matter(e.g., extracted from plant matter such as plant waste from otherapplications). Extracting the monomer and/or oligomer units of plantextract can be performed instead of purchasing fatty acids fromcommercial sources, or as a supplement to fatty acids from commercialsources. Plant matter typically includes some portions that containcutin and/or have a high density of cutin (e.g., fruit peels, leaves,shoots, etc.), as well as other portions that do not contain cutin orhave a low density of cutin (e.g., fruit flesh, seeds, etc.). Thecutin-containing portions can be formed from the monomer and/or oligomerunits and can also include other constituents such as proteins,polysaccharides, phenols, lignans, aromatic acids, terpenoids,flavonoids, carotenoids, alkaloids, alcohols, alkanes, and aldehydes.The non-cutin-containing portions typically lack the monomer and/oroligomer units, or otherwise include a much lower ratio of monomerand/or oligomer units to other constituents as compared to thecutin-containing portions.

Methods described herein for forming plant extract compositions fromcutin can generally include first separating (or at least partiallyseparating) cutin-containing portions of plant matter fromnon-cutin-containing portions, and obtaining cutin from thecutin-containing portions (e.g., when the cutin-containing portion is afruit peel, the cutin is separated from the peel). The cutin is thendepolymerized (or at least partially depolymerized) in a first solventto obtain a first solution comprising a first intermediate extractdissolved in the first solvent, the first intermediate extract includinga plurality of fatty acid or esterified cutin monomers, oligomers, orcombinations thereof. The first solvent (and therefore the resultingfirst solution) typically has a pH in the range of 10 to 14, in order toenable the depolymerization process. The high pH indicates that theextract is substantially deprotonated. In some embodiments, the firstsolvents and/or the first solution has a pH in the range of 12 to 14.Following depolymerization, the extract including the monomer and/oroligomer units is acidified in order for the monomer and/or oligomerunits to be protonated or rendered neutral (i.e., to generate thecorresponding free fatty acids and/or fatty esters and to be in a statethat enables them to subsequently form an agricultural coating).Finally, the extract including the free fatty acid and/or free fattyester monomer and/or oligomer units is dissolved in another solvent,thereby resulting in a plant extract composition suitable foragricultural coating applications.

Because the cutin obtained from the cutin-containing portion istypically intermixed with many of the other constituents describedabove, the extract obtained from the depolymerization process may have ahigher level of impurity constituents than can be tolerated inagricultural coating applications. As such, the cutin and/or the extractcomposition and/or the solution containing the extract composition canbe purified by selectively removing or filtering out the impurityconstituents. Selective filtering can occur either before or after thedepolymerization process, or both before and after depolymerization.Selective filtering may include one or more of the following processes:

-   -   (a) Prior to depolymerizing or partly depolymerizing the cutin,        washing and/or heating the cutin in a selective solvent for        which the solubility of impurity constituents in the selective        solvent is higher than the solubility of the cutin. In this        case, impurities are dissolved into the selective solvent,        thereby resulting in fewer impurities in the first intermediate        extract. In some embodiments, impurities are dissolved into the        selective solvent immediately after depolymerization. Examples        of such a solvent can include chloroform, diethyl ether,        dichloromethane, hexane, petroleum ether, ethyl acetate,        acetone, isopropanol, ethanol, methanol, supercritical carbon        dioxide, supercritical water, water, and mixtures thereof.    -   (b) After depolymerizing or partly depolymerizing the cutin to        obtain the first solution comprising the first intermediate        extract dissolved in the first solvent, and prior to acidifying        the first intermediate extract, washing and/or heating the first        intermediate extract in a selective solvent (e.g., acetonitrile)        for which the solubility of impurity constituents in the        selective solvent is lower than the solubility of the monomers        and/or oligomers. In this case, the monomers and/or oligomers        are dissolved into the selective solvent while the impurities        are not. The impurities can then be filtered out, resulting in a        second intermediate extract dissolved in the selective solvent,        whereby the second intermediate extract has a higher purity than        the first intermediate extract. The second intermediate extract        may subsequently be solidified, e.g., by evaporating the        selective solvent.    -   (c) After depolymerizing or partly depolymerizing the cutin to        obtain the first solution comprising the first intermediate        extract dissolved in the first solvent, and prior to acidifying        the first intermediate extract, washing and/or heating the first        intermediate extract in a selective solvent (e.g., chloroform or        hexane) for which the solubility of impurity constituents in the        selective solvent is higher than the solubility of the monomers        and/or oligomers. In this case, impurities are dissolved into        the selective solvent, thereby removing the impurities from the        extract, and a second intermediate extract having a higher        purity than the first intermediate extract is obtained.    -   (d) After depolymerizing or partly depolymerizing the cutin to        obtain the first solution comprising the first intermediate        extract dissolved in the first solvent, and after subsequently        acidifying the first intermediate extract, washing and/or        heating the first intermediate extract in a selective solvent        (e.g., acetonitrile) for which the solubility of impurity        constituents in the selective solvent is lower than the        solubility of the monomers and/or oligomers. In this case, the        monomers and/or oligomers are dissolved into the selective        solvent while the impurities are not. The impurities can then be        filtered out, resulting in a second intermediate extract        dissolved in the selective solvent, whereby the second        intermediate extract has a higher purity than the first        intermediate extract. The second intermediate extract may        subsequently be solidified, e.g., by evaporating the selective        solvent.    -   (e) After depolymerizing or partly depolymerizing the cutin to        obtain the first solution comprising the first intermediate        extract dissolved in the first solvent, and after subsequently        acidifying the first intermediate extract, washing and/or        heating the first intermediate extract in a selective solvent        (e.g., chloroform or hexane) for which the solubility of        impurity constituents in the selective solvent is higher than        the solubility of the monomers and/or oligomers. In this case,        impurities are dissolved into the selective solvent, thereby        removing the impurities from the extract, and a second        intermediate extract having a higher purity than the first        intermediate extract is obtained.    -   (f) After obtaining a compound comprising cutin from a        cutin-containing portion of plant matter and prior to        depolymerizing or partly depolymerizing the cutin, exposing the        compound to supercritical carbon dioxide to selectively reduce a        concentration of at least one of proteins, polysaccharides,        phenols, lignans, aromatic acids, terpenoids, flavonoids,        carotenoids, alkaloids, alcohols, alkanes, aldehydes, and waxes.    -   (g) After depolymerizing or partly depolymerizing the cutin to        obtain the first solution comprising the first intermediate        extract dissolved in the first solvent, and either prior to or        after acidifying the first intermediate extract, filtering the        solution to remove undissolved impurity constituents, for        example by passing the solution through a filter.

In some embodiments, at least a portion of the plant extract can includemonomers that include multiple functional groups (e.g., one of at leasthydroxyl, carboxyl, epoxy, olefin, etc.). For example, in someembodiments, the monomers can include multiple functional groups of thesame type (e.g., dihydroxy- and trihydroxy-substituted). In someembodiments, the monomers can include multiple functional groups, atleast one of which is different than the remaining functional group(s)(i.e., includes more than one type of functional group). Thesefunctional groups can be chemically reactive, allowing the formation ofhighly crosslinked networks, unlike their monofunctional analogs (whichform dimers), or their di-functional analogs (which can polymerize intolinear chains). The barrier properties (i.e., the ability of suchextracts to form an effective agricultural coating/barrier againstbiotic or abiotic stressors) are generally controlled by the chemicalcomposition and degree of crosslinking. Polyhydroxy fatty acids (as wellas their monomeric esters and oligomers) are multifunctional and thuscapable of forming highly crosslinked polymers. However, suchpolyhydroxy fatty acids are not currently commercially available. Thus,such hydroxy fatty acids can either be synthesized or obtained from asuitable biological source. Since the cutin of many plants and/or plantorgans (e.g., fruit peels, juice sac, leaves, shoots, etc.) is composedof mono- and polyhydroxy fatty acids (or can be decomposed into mono- orpolyhydroxy fatty acids), an extract composition from such plants and/orplant organs can provide a suitable biological source of mono- and/orpolyhydroxy fatty acids.

In some embodiments, the cutin monomers included in the plant extractcompositions described herein can be mono- and/or polyhydroxy fattyacids and/or esters thereof in a combination suitable for use in coatingformulations, e.g. for protecting plant species against environmentaland/or biotic stressors. Since bacteria, fungi, and pests all identifyfood sources via recognition of specific molecules on the surface ofagricultural products, coating agricultural products with a formulationthat includes embodiments of the plant extract compositions describedherein can render the agricultural products unattractive orunrecognizable to said bacteria, fungi, and pests. Such formulationscan, for example, also alter the chemical environment of the surface ofagricultural products, making the surface unfavorable for bacteria,fungi, or pests to grow. Moreover, such formulations can also beconfigured to simultaneously prevent moisture loss from agriculturalproducts and/or their oxidation by ambient air and/or impart resistanceto mechanical damage and/or photodegradation and/or delay ripening,thereby minimizing decomposition and increasing the life of theagricultural products by aiding in resistance to abiotic stressors.

Embodiments of the plant extract compositions described herein can besynthesized or extracted from plant matter, including agricultural wasteproducts, and can be included in coating formulations for protectingagricultural products from environmental and biotic stressors.Embodiments of the plant extract compositions described herein provideseveral advantages, including, for example: (1) formation ofagricultural coating formulations that can protect the agriculturalproducts from biotic stressors (i.e., bacteria, viruses, fungi, orpests); (2) formation of agricultural coating formulations that canprevent evaporation of water and/or diffusion of oxygen and/or othergaseous species (e.g., carbon dioxide and ethylene); (3) extension ofthe shelf life of agricultural products, for example, postharvestproduce, without refrigeration; (4) introduction of mechanical stabilityto the surface of the agricultural products, helping to prevent thetypes of bruising and surface rupture that accelerate spoilage; (5)reduction of photodegradation of the agricultural products; (6) use ofagricultural waste materials to obtain the plant extract compositions,which in turn help eliminate the breeding environments of bacteria,fungi, and pests, and divert materials away from landfills; (7) use inplace of pesticides to protect plants, thereby minimizing the harmfulimpact of pesticides to human health and the environment; and (8)extraction from natural and/or edible waste products, making the plantextract compositions safe for human consumption.

A method for preparing a plant extraction composition can includethermally and/or mechanically and/or enzymatically and/or chemicallytreating the plant matter to at least partially separate thecutin-containing portion from the non-cutin-containing portion of theplant matter. In some embodiments, the plant matter is subjected toelevated temperature and/or pressure in an aqueous medium (e.g., as inpressure cooking) to partially separate the cutin-containing portionfrom the non-cutin-containing portion of the plant matter.Alternatively, the plant matter may be subjected to lower temperatures(e.g., as in freezing) to partially separate the cutin-containingportion from the non-cutin-containing portion of the plant matter. Insome embodiments, the plant matter is subjected to sonication in anaqueous medium to partially separate the cutin-containing portion fromthe non-cutin-containing portion of the plant matter. Optionally, thecutin-containing portion is heated in a mixture of ammonium oxalate andoxalic acid to aid separation of the cutin from the non-cutin-containingportion (i.e., the remainder of the cuticle and unwanted plant matter).Optionally, this separation can be achieved (or assisted) enzymaticallyusing enzymes capable of hydrolyzing ester bonds and/or alternativelyusing enzymes capable of breaking down polysaccharides that comprise thenon-cutin-containing portion of the plant. Optionally, thecutin-containing portion is refluxed in at least one organic solvent(such as chloroform and/or methanol) to remove residual waxes and/or anyremaining soluble polar components from the cutin. Alternatively,removal of residual waxes and remaining soluble components can beachieved using supercritical CO₂ or supercritical H₂O.

The cutin (or cutin-containing component) obtained from the plant matteris then refluxed in a solvent having a high pH (e.g., in the range ofabout 10 to 14, and typically in the range of 12 to 14), for example asolvent which is alkalized with metal alkoxide or metal hydroxide (oralternative source of alkoxide or hydroxide) to at least partiallydepolymerize the cutin and obtain an intermediate extract including aplurality of esterified or fatty acid cutin monomers, their oligomers,or mixtures thereof. The high pH solvent can be one in which themonomers and/or oligomers are highly soluble, but one or more of theother constituents of the cutin-containing compound (e.g., proteins,polysaccharides, phenols, lignans, aromatic acids, terpenoids,flavonoids, carotenoids, alkaloids, alcohols, alkanes, and aldehydes) isinsoluble or is less soluble than the monomers and/or oligomers. Assuch, after the depolymerization process, the non-dissolved impuritiescan be filtered from the solution. In some embodiments, the high-pHsolvent includes ethanol, methanol, or another alcohol having metal(e.g., sodium metal), metal alkoxide, or metal hydroxide dissolvedwithin.

In some embodiments, the high-pH solvent is substantially free of water(e.g., less than 5% water by mass) or has a relatively low water content(e.g., less than 50%, less than 40%, less than 35%, less than 30%, lessthan 25%, less than 20%, less than 15%, or less than 10% water by mass).Without wishing to be bound by theory, the use of non water-containingor low water content solvents has been found to cause the resultingplant extract compositions, when solidified (e.g., after removal of thesolvent from the composition), to be much more tractable (e.g., to be asolid powder rather than a sticky mass), and to have substantiallyreduced coloration. That is, even after subsequent purification steps,solidified plant extract compositions that were formed viadepolymerization of cutin in a high-pH solvent containing a substantialamount of water (e.g., greater than 50% water by mass) were found toresult in a sticky mass with a substantial amount of coloration, whereasextract compositions formed via cutin depolymerization in a nonwater-containing or low water content solvent were able to be purifiedinto a yellow/orange to colorless free flowing powder. It has been foundthat agricultural coatings formed from plant extract compositions withlow coloration and with the powdery consistency described above can besubstantially undetectable to the human eye, without modifying theappearance of the agricultural product to which they are applied. On theother hand, coatings formed from extracts with higher levels ofcoloration and/or sticky cannot be deposited as uniformly and may causethe coated agricultural product to appear discolored and/or damaged.

The reasons for the substantial difference in color and consistency ofthe resulting solidified compositions when water-containing and nonwater-containing (or low water content) solvents are used fordepolymerization are unclear. However, without wishing to be bound bytheory, it is hypothesized that the steric bulk of the nucleophiledictates the species that are depolymerized, including trace components,and that an undesirable mix of depolymerized species and tracecomponents resulting from depolymerization in water containing solventsgives rise to color and/or sticky consistency in the extractcomposition.

Next, the solution comprising the intermediate extract dissolved in thehigh pH solvent is acidified in order to cause the monomer and/oroligomer units to be protonated or rendered neutral (i.e., to generatethe corresponding free fatty acids and/or fatty esters and to be in astate that enables them to subsequently form an agricultural coating).In cases where the intermediate extract is obtained from (metal)alkoxide-mediated depolymerization, the pH of the solvent andintermediate extract can be adjusted to be in the range of about 6.5 to9.0. In cases where the intermediate extract is obtained from (metal)hydroxide-mediated depolymerization, the pH of the solvent andintermediate extract can be adjusted to be in the range of about 1.0 to6.5. Alternatively, rather than depolymerizing in an alkalized solventand subsequently acidifying, the cutin can be at least partiallydepolymerized under acidic conditions to obtain an intermediate extractincluding a plurality of fatty acid cutin monomers, oligomers, ormixtures thereof.

The intermediate extract is then precipitated and/or extracted andpurified (such as by washing with one or more selective solvents) toobtain the plant extract such that the plant extract is substantiallyfree from accompanying plant-derived compounds (e.g., proteins,polysaccharides, phenols, lignans, aromatic acids, terpenoids,flavonoids, carotenoids, alkaloids, alcohols, alkanes, and aldehydes).Further purification by chromatography or recrystallization in selectivesolvent may also be carried out after washing to obtain the finalextract.

In some embodiments, after depolymerization in the high pH solvent toobtain the intermediate extract, instead of directly acidifying the highpH solvent and the dissolved intermediate extract, the intermediateextract is first precipitated (i.e., solidified), for example byevaporating at least a portion (and in some cases substantially all of)the high pH solvent. The solidified intermediate extract is thendissolve in a polar solvent such as water in order to obtain a secondsolution, and the second solution is then acidified to a pH in the rangeof 1 to 6.5. Acidifying the second solution comprising the polar solventand the intermediate extract may cause the intermediate extract toresolidify, after which the intermediate extract can be filtered out ofthe second solution. The resolidified intermediate extract can then bedissolved in another solvent, for example ethanol, to form the finalplant extract composition. Alternatively, the resolidified intermediateextract can be selectively filtered to remove additional impurities andthereby obtain a second intermediate extract having a higher purity thanthe intermediate extract. For example, the second intermediate extractcan be obtained by washing the intermediate extract in acetonitrile, aspreviously described. Finally, the second intermediate extract can bedissolved in another solvent, for example ethanol, to form the finalplant extract composition.

In still other embodiments, after depolymerization in the high pHsolvent to obtain the intermediate extract, instead of directlyacidifying the high pH solvent and the dissolved intermediate extract,at least 25% of the high pH solvent is first evaporated, a polar solventsuch as water is then added to form a second solution, and the secondsolution is then acidified to a pH in the range of 1 to 6.5. Acidifyingthe second solution comprising the polar solvent and the intermediateextract may cause the intermediate extract to precipitate (i.e.,solidify), after which the intermediate extract can be filtered out ofthe second solution. The solidified intermediate extract can then bedissolved in another solvent, for example ethanol, to form the finalplant extract composition. Alternatively, the solidified intermediateextract can be selectively filtered to remove additional impurities andthereby obtain a second intermediate extract having a higher purity thanthe intermediate extract. For example, the second intermediate extractcan be obtained by washing the intermediate extract in acetonitrile, aspreviously described. Finally, the second intermediate extract can bedissolved in another solvent, for example ethanol, to form the finalplant extract composition.

As used herein, “plant matter” refers to any portion of a plant thatcontains cutin including, for example, fruits (in the botanical sense,including fruit peels and juice sacs), leaves, stems, barks, seeds,flowers, or any other portion of the plant.

As used herein, the terms “about” and “approximately” generally meanplus or minus 10% of the value stated. For example, “about 250 μm” wouldinclude 225 μm to 275 μm, and “about 1,000 μm” would include 900 μm to1,100 μm.

FIG. 1 shows a schematic flow diagram of a method 100 for preparing aplant extract composition. The method 100 includes thermally treating aplant matter to at least partially separate a cutin-containing portionfrom the plant matter, at 102. The thermal treating can include, forexample, heating the plant matter (e.g., with steam, in water or inanother solvent), freezing the plant, or subjecting the plant matter tocyclic thermal treatments. The plant matter can include any suitableplant matter or otherwise agricultural product such as, for example,fruits (including fruit peels and juice sacs), leaves, stem, barks,seeds, and flowers. In some embodiments, the plant matter can includeagricultural waste products such as, for example, tomato peel, grapeskins, apple peel, pepper peel, lemon peel, lemon leaf, lime peel, limeleaf, orange peel, orange leaf, orange fruit, clementine leaf,clementine fruit, mandarin leaf, mandarin fruit, pea seeds, grapefruitpeel, grapefruit leaf, grapefruit seed, papaya peel, cherry fruits,cranberry skins, coffee cherries, grass clippings, or any other plantsor portions of plants that can yield any embodiment of the plant extractcompositions described herein. In some embodiments, the plant matter canbe a fruit (e.g., a tomato, cranberry, or grape) and thecutin-containing portion can be a peel of the fruit (e.g., a tomato peelor cranberry skin or grape skin) such that the boiling can at leastpartially separate the peel from the fruit. The fruit can be washed toremove surface residue, waxes, or otherwise debris before operation 102.Furthermore, the fruit can be cut into halves, quarters, or small piecesor ground to finer pieces and then boiled until the peels or otherwiseskins are visibly separated from the fruit pulp.

The method 100 can optionally include mechanically processing the plantmatter to at least partially separate the cutin-containing portion fromthe plant matter, at 104. The mechanical process can be performed beforeand/or after thermal treatment of the plant matter (i.e., 102) (e.g.,boiling of the plant matter in water) to facilitate separation of thecutin-containing portion from the plant matter. Suitable mechanicalprocesses can include, for example, centrifugation, (ultra)sonication,pressing, ball milling, grinding, etc. In some embodiments, mechanicalseparation can include separating a fruit peel from the fruit pulp. Insome embodiments, mechanical removal of the pulp might not be performedand the fruit skins (e.g., waste fruit skins leftover after processingof the fruit) may be macerated, blended, cut, shredded, food processed,or otherwise subjected to some other mechanical treatment operation tophysically breakdown the fruit skins into smaller or finer pieces. Insome embodiments, a plurality of intermediate mechanical processes canbe used to obtain the plant extract composition. For example, amechanical step can be used to separate the cutin from thenon-cutin-containing portion, as described herein, or be used to augmentany other operation included in the method 100. Such mechanicalprocesses can include any of the mechanical processes described hereinsuch as, for example, centrifugation, sonication, (ultra)sonication,milling, grinding, filtration, etc.

The cutin-containing portion is then optionally heated in a mixture ofammonium oxalate and oxalic acid to separate the cutin from thenon-cutin-containing portion, at 106. Optionally this process can alsobe achieved (or assisted) using enzymes capable of breaking downpolysaccharides or pectin. For example, the cutin can include thecuticular layer of the plant matter. The heating in the ammonium oxalateand oxalic acid mixture disrupts the pectinaceous glue that attaches thecuticle to the underlying cells of the plant matter and helps releasethe cuticle. Furthermore, this step disrupts the pectinaceous glue thatis found within primary cell walls and between plant cells (e.g., in themiddle lamella that binds neighboring cells), aiding in the isolation ofa cutin-containing portion. In this manner, the ammonium oxalate andoxalic acid solution can facilitate at least partial chemical detachmentof remaining debris from the cutin-containing portion of the plant(e.g., removal of any remaining pulp from the fruit peel). The heatingcan be performed at any suitable temperature (e.g., 35 degrees Celsius,50 degrees Celsius, 55 degrees Celsius, 60 degrees Celsius, 65 degreesCelsius, 70 degrees Celsius, 75 degrees Celsius, 80 degrees Celsius, 85degrees Celsius, 90 degrees Celsius, 95 degrees Celsius, or 100 degreesCelsius, inclusive of all ranges and values therebetween and for anysuitable time (this process can be accelerated if carried out underelevated pressure). For example, in some embodiments, thecutin-containing portion can be heated in the mixture of ammoniumoxalate and oxalic acid at a temperature of about 75 degrees Celsius forabout 24 hours. In some embodiments, the portion of the plant, forexample, the fruit peel, after treatment with the ammonium oxalate andoxalic acid solution, can be isolated by filtration and dried (e.g.,air-dried under ambient conditions, oven-dried or freeze-dried) toremove any residual water.

In some embodiments, the cutin can optionally be treated with an enzyme,at 108. For example, the cutin can be treated with an enzyme such as acarbohydrate-hydrolyzing enzyme to digest or otherwise removecarbohydrates (e.g., cellulose or pectin) attached to or embedded withinthe cutin. Such enzymes can include, for example, naturally derived orsynthetic cellulases, pectinases, and hemicellulases. The enzymaticdegradation can be used before, after, or otherwise in place ofoperation 106 to obtain the cutin from the non-cutin-containing portion.In some embodiments, the reverse process may be employed wherein thecutin can be treated with an enzyme that can at least partiallydepolymerize the cutin to yield cutin oligomers or any combination ofcutin oligomers and cutin monomers to leave behind thenon-cutin-containing components, which could be filtered out orotherwise separated. Such enzymes can include, for example, cutinases,esterases, or lipases.

Optionally, the cutin is refluxed in at least one suitable solvent(e.g., chloroform and/or methanol) to remove soluble waxes or polarimpurities from the cutin, at 110. For example, the cutin can berefluxed only in chloroform, refluxed in chloroform followed byrefluxing in methanol, refluxed only in methanol, or refluxed in amixture of chloroform and methanol, or any other suitable solvent(s) (orcombinations thereof) in which the wax and/or polar components aresoluble. In some embodiments, the cutin can be refluxed in a dilutesolution of a strong base (e.g., potassium hydroxide in water or inalcoholic solvent), or a solution of a moderately strong or weak base(e.g., potassium carbonate in water or in alcoholic solvent) to removesoluble pigmented impurities. Alternatively, removal of residual waxesand remaining soluble components can be achieved using supercritical CO₂or supercritical H₂O. The refluxing can be performed at any suitabletemperature and for any suitable length of time. For example, in someembodiments, the cutin can be refluxed in chloroform at about 60-65degrees Celsius for about 24-36 hours to remove any wax and/or non-polarcompounds embedded in the cutin. This can be followed by refluxing inmethanol at 65-70 degrees Celsius for about 4-12 hours, for example, toremove any polar organic components (e.g., flavonoids and flavonoidglycosides) present in the cutin. The completion of the operation can bedetermined by the clarity of solvents. For example, the process can bemonitored with instrumentation (e.g., NMR, GC-MS, React-IR, FTIR,spectrophotometry, etc.) configured to analyze the clarity of thesolvents and can continue until a predetermined clarity is achieved.Each of the chloroform and/or methanol extraction processes can beperformed in any apparatus capable of refluxing (i.e., recirculatingand/or recycling) the solvents such as, for example, a reaction flaskequipped with a condenser, a Soxhlet apparatus, a Kumagawa extractor, anultrasound assisted extractor, a robot automated extractor, or any othersuitable extraction apparatus. Such an apparatus can, for example,reduce the amount of solvent used in the extraction process. Any othersolvent or combinations thereof (i.e., a binary or ternary mixture) canbe used to wash out undesired impurities. Suitable solvents can include,for example, diethyl ether, dichloromethane, hexane, petroleum ether,ethyl acetate, acetone, isopropanol, ethanol, acetonitrile,supercritical carbon dioxide, supercritical water, water, and mixturesthereof. In some embodiments, multiple extraction steps in one or moresolvents can also be performed. In some embodiments, intermediateenzymatic treatment steps can also be performed between the solventextraction processes, for example, to liberate undesired compounds fromthe cutin. The solution obtained after operation 110 can include arelatively pure sample of the cutin included in the portion of the plantalong with any residually attached or embedded polysaccharides (e.g.,cellulose), plant metabolites (e.g., flavonoids), and/or proteins.

The cutin is then heated in a solution of metal alkoxide or metalhydroxide to at least partially depolymerize the cutin and obtain anintermediate extract including a plurality of monomeric and/oroligomeric fatty cutin esters and/or acids (or combinations thereof), at112. The metal alkoxide can include, for example, sodium methoxide,sodium ethoxide, sodium iso-propoxide, sodium n-propoxide, sodiumiso-butoxide, sodium n-butoxide, potassium methoxide, potassiumethoxide, potassium iso-propoxide, potassium n-propoxide, potassiumiso-butoxide, or potassium n-butoxide. The metal hydroxide can include,for example, Group I or Group II metal hydroxides, such as lithium,sodium, potassium, calcium, rubidium, or cesium hydroxide. Also includedare precursors or compounds that will generate alkoxide or hydroxide ina suitable reaction medium (such as neat metals (e.g., sodium metal) oroxides in methanol, or ammonia in water). Refluxing of the cutin in thepresence of the metal alkoxide or metal hydroxide can be performed atany suitable temperature and for any suitable length of time such as,for example, at about 65 degrees Celsius for about 24 hours. In someembodiments, refluxing of the cutin in the presence of the metalalkoxide to obtain fatty esters (or oligomers thereof) can be carriedout in anhydrous reagents, anhydrous solvents, a closed atmosphere,and/or a nitrogenous atmosphere in order to favor ester formation oversaponification and acid formation. In some embodiments, the temperatureand/or the refluxing time can be such that the cutin is only partiallydepolymerized to yield a predetermined combination of oligomers andmonomers. In some embodiments, the temperature and/or the refluxing timecan be adjusted such that the cutin is mostly depolymerized by the metalalkoxide or metal hydroxide into a plurality of monomeric cutin-derivedfatty esters or fatty acids, respectively. In some embodiments, therefluxing in the metal alkoxide or metal hydroxide can be performed in amixture of the metal alkoxide or metal hydroxide and a solvent, forexample, methanol, ethanol, hexane, toluene, etc. In the case of cutindepolymerization with metal hydroxide, water can also be used as asolvent to obtain cutin-derived fatty acids. In some embodiments, thesolvent can include methanol. The concentration of metal alkoxide,solvent, and/or the pH of the solution can, for example, facilitate thepreservation of the depolymerized cutin components in monomeric ester oracid form, which can prevent oligomerization or repolymerization of theliberated cutin monomers included in the intermediate extract. In someembodiments, the depolymerization and transesterification of the cutinto obtain esterified cutin monomers can be performed by refluxing in asolution of methanol containing boron trifluoride and/or a metalalkoxide (e.g., sodium methoxide).

In some embodiments, after depolymerization, any undepolymerized solidscan be removed from the reaction mixture by, for example, filtration orcentrifugation. The filtrate containing solubilized cutin monomers isthen subjected to pH adjustment. The pH of the intermediate extractobtained after depolymerization with metal alkoxide is adjusted to be inthe range of about 6.5 to 9.0 at 114, inclusive of all ranges and valuestherebetween. In some embodiments, the pH of the intermediate extractobtained after depolymerization with metal hydroxide is adjusted to bein the range of about 1.0 to about 6.5, at 114. In some embodiments, thepH adjustment can be directly carried out in the depolymerizationreaction medium (e.g., methanolic KOH). Optionally, the reaction solventcan be removed, for example, by evaporation to obtain a crude,concentrated extract that can then be reconstituted in a solventdifferent from the depolymerization reaction (e.g., evaporation ofmethanol and reconstitution with water) prior to pH adjustment. Forexample, the pH can be adjusted to be in the range of 1.5 to about 6.5,about 2 to about 6.5, about 2.5 to about 6.5, about 3 to about 6.5,about 3.5 to about 6.5, about 4 to about 6.5, about 4.5 to about 6.5,about 5 to about 6.5, or about 5.5 to about 6.5, inclusive of all rangesand values therebetween. The adjusting of the pH can be performed usingany suitable acid such as, for example, citric acid, acetic acid,hydrochloric acid, sulfuric acid, phosphoric acid, hydrobromic acid,ascorbic acid, tartaric acid, formic acid, gluconic acid, lactic acid,oxalic acid, boric acid, any other suitable acid, any other suitable pHadjusting agent, or a combination thereof. In some embodiments, theadjusting of the pH can be sufficient to protonate a secondary and/or aprimary hydroxyl group of the plurality of esterified cutin monomers,but insufficient to protonate a carboxylate group present as a result ofdepolymerization at alkaline pHs. For example, in some embodiments, theliberated cutin monomers can include esters of a fatty acid, a hydroxyfatty acid, a dihydroxy fatty acid, and/or a trihydroxy fatty acid. Insome embodiments, the liberated cutin monomers can include a fatty acid,a hydroxy fatty acid, a dihydroxy fatty acid, and/or a trihydroxy fattyacid. In some embodiments, the liberated cutin monomers can include thesalts of a fatty acid, a hydroxy fatty acid, a dihydroxy fatty acid,and/or a trihydroxy fatty acid. Upon lowering the pH of the intermediateextract that includes one or more of these hydroxy fatty esters oracids, the secondary hydroxyl groups are protonated first (included indihydroxy fatty acids and trihydroxy fatty acids), followed by theprimary hydroxyl groups (included in trihydroxy fatty acids, dihydroxyfatty acids, and monohydroxy fatty acids). Any further lowering of thepH of the intermediate extract obtained from hydroxide-mediated cutindepolymerization can also protonate the carboxylate group of theobtained cutin monomers, which will modify solubility of the monomers ina polar reaction medium. Therefore, the pH can be adjusted such that thedegree of protonation can be controlled so as to tune downstream methodsof monomer isolation. For example, in some embodiments, the pH of asolution of the intermediate extract can be adjusted so as topreferentially promote precipitation of the fatty acid cutin monomers(and oligomers) from the solution and facilitate recovery of themonomers (and oligomers) by, for example, filtration or centrifugation.In this example, the pH of a solution of the intermediate extract inwater can be adjusted to be about pH 1-3 such that fatty cutin monomers(and oligomers) precipitate from the solution and the solids can berecovered by filtration or centrifugation.

The intermediate extract is resolidified at 116. The resolidificationcan include, for example, precipitation of the cutin-derived fattyesters or fatty acids from the solution by evaporation of the solvent(s)or addition of an agent that induces precipitation (such as salts,acids, unfavorable solvents, or co-precipitation agents).

Optionally, the crude extract can be purified by washing of theprecipitated extract with a selective solvent (e.g., acetonitrile) orcombinations of selective solvents, at 118, and/or recrystallization ofthe extracted cutin monomers, at 120, and/or chromatographic separationand isolation of the cutin monomers, at 122.

In some embodiments, the crude extract is refluxed in at least onesuitable solvent or (e.g., acetonitrile, acetone, etc.) or combinationsthereof to remove oligomeric, phenolic, and colored impurities, at 118.Alternatively, removal of oligomeric, phenolic, and colored impuritiescan be achieved using supercritical CO₂ or supercritical H₂O. Therefluxing can be performed at any suitable temperature and for anysuitable length of time. For example, in some embodiments, the crudeextract can be refluxed in acetonitrile at about 80-85 degrees Celsiusfor about 24-36 hours to solubilize monomeric components, leaving behinda partly soluble and/or insoluble residue of oligomeric, phenolic, andcolored impurities. The completion of the operation can be determined bythe clarity of the monomer-enriched solution. For example, the processcan be monitored with instrumentation (e.g., NMR, GC-MS, React-IR, FTIR,spectrophotometry, etc.) configured to analyze the clarity of thesolvents and can continue until a predetermined clarity is achieved. Thepost-depolymerization extraction processes can be performed in anyapparatus capable of refluxing (i.e., recirculating and/or recycling)the solvents such as, for example, a Soxhlet apparatus, a Kumagawaextractor, an ultrasound assisted extractor, a robot automatedextractor, or any other suitable extraction apparatus. Such an apparatuscan, for example, reduce the amount of solvent used in the extractionprocess. Any other solvent or combinations thereof (i.e., a binary orternary mixture) can be used to wash out undesired impurities. Suitablesolvents can include, for example, diethyl ether, dichloromethane,hexane, petroleum ether, ethyl acetate, acetone, isopropanol, ethanol,acetonitrile, supercritical carbon dioxide, supercritical water, water,and mixtures thereof In some embodiments, multiple extraction steps inone or more solvents can also be performed. In some embodiments,intermediate enzymatic treatment steps can also be performed between thesolvent extraction processes, for example, to liberate undesiredcompounds from the crude extract. The resulting solution can beresolidified. The resolidification can include, for example,precipitation of the cutin-derived fatty esters or fatty acids from thesolution by evaporation of the solvent(s) or addition of an agent thatinduces precipitation (such as salts, unfavorable solvents, orco-precipitation agents). The plant extract obtained using the method100 can be substantially free of accompanying plant-derived compounds(e.g., proteins, polysaccharides, phenols, lignans, aromatic acids,terpenoids, flavonoids, carotenoids, alkaloids, alcohols, alkanes, andaldehydes).

In some embodiments, the plant extract composition obtained using themethod 100 or any other method described herein, can include anysuitable combination of cutin monomers including, for example,C₁₆-ω-hydroxy fatty acids, and/or C₁₆ hydroxy fatty acids, and/or C₁₆dihydroxy fatty acids, and/or C₁₆ trihydroxy fatty acids, and/orC₁₆-ω-hydroxy-oxo fatty acids, and/or C₁₈-ω-hydroxy fatty acids, and/orC₁₈ hydroxy fatty acids, and/or C₁₈ dihydroxy fatty acids, and/or C₁₈trihydroxy fatty acids, and/or C₁₈-ω-hydroxy-oxo fatty acids, and/orC₁₈-ω-hydroxy-epoxy fatty acids, and residual fatty acids, and/or estersof said families of C₁₆ hydroxy fatty acids and/or C₁₈ hydroxy fattyacids and residual fatty acids. For example, in some embodiments, theplant extract composition can include a first fraction including C₁₆hydroxy fatty acids or C₁₆ hydroxy fatty esters in the range of about 15wt % to about 100 wt %, a second fraction including C₁₈ hydroxy fattyacids or C₁₈ hydroxy fatty esters in the range of 0 wt % to about 90 wt%, and a third fraction including residual fatty acids or residual fattyesters in the range of about 0 wt % to about 75 wt %. In someembodiments, the plant extract composition can include a first fractionincluding C₁₆ hydroxy fatty acids or C₁₆ hydroxy fatty esters in therange of about 50 wt % to about 100 wt %, a second fraction includingC₁₈ hydroxy fatty acids or C₁₈ hydroxy fatty esters in the range of 0 wt% to about 35 wt %, and a third fraction including residual fatty acidsor residual fatty esters in the range of about 0 wt % to about 23 wt %.In some embodiments, the combination and relative concentration of theC₁₆ hydroxy fatty acids (or C₁₆ hydroxy fatty esters), the C₁₈ hydroxyfatty acids (or C₁₈ hydroxy fatty esters), and the residual fatty acids(or residual fatty esters) can be controlled by adjusting the processparameters (e.g., depolymerization conditions, and choice ofpost-depolymerization extraction, resolidification, wash, andpurification conditions) included in the method 100, or by blending theextracts from multiple plant sources. The C₁₆ hydroxy fatty acids caninclude, but are not limited to, at least one of 16-hydroxyhexadecanoicacid, 9(10),16-dihydroxyhexadecanoic acid,9,10,16-trihydroxyhexadecanoic acid, and 16-hydroxy-10-oxohexadecanoicacid. The C₁₆ hydroxy fatty esters can include, but are not limited to,at least one of methyl 16-hydroxyhexadecanoate, methyl9(10),16-dihydroxyhexadecanoate, methyl 9,10,16-trihydroxyhexadecanoate,and methyl 16-hydroxy-10-oxohexadecanoate. The C₁₈ hydroxy fatty acidscan include at least one of 18-hydroxyoctadecanoic acid,9(10),18-dihydroxyoctadecanoic acid, 9,10,18-trihydroxyoctadecanoicacid, and 18-hydroxy-9,10-epoxy-octadecanoic acid. The C₁₈ hydroxy fattyesters can include at least one of methyl 18-hydroxyoctadecanoate,methyl 9(10),18-dihydroxyoctadecanoate, methyl9,10,18-trihydroxyoctadecanoate, and methyl18-hydroxy-9,10-epoxy-octadecanoate.

For example, in some embodiments, the first fraction can include about50 wt % to about 100 wt % of a 9(10),16-dihydroxyhexadecanoic acid (orthe ester thereof), about 2 wt % to about 27 wt % of a16-hydroxyhexadecanoic acid (or the ester thereof), and 0 wt % to about35 wt % of a 16-hydroxy-10-oxohexadecanoic acid (or the ester thereof).In some embodiments, the second fraction can include at least 0 wt % toabout 100 wt % of a 9,10,18-trihydroxyoctadecanoic acid (or the esterthereof). In some embodiments, the second fraction can also include 0 wt% to about 8 wt % of a 9,10,18-trihydroxyoctadecanoic acid (or the esterthereof), at least 0 wt % to about 9 wt % of a ω-hydroxyoctadecanoicacid (or the ester thereof), and/or at least 0 wt % to about 33 wt % ofa ω-hydroxy-9,10-epoxy-octadecanoic acid (or the ester thereof). Theresidual fatty acids (and/or fatty esters) can include any other fattyacids (or fatty esters) excluding C₁₆ and C₁₈ hydroxy fatty acids (orfatty esters) in any proportion or combination such as, for example,hexadecanoic acid, dicarboxylic acids,9,10-dihydroxyhexadecane-1,16-dioic acid, 9,12-octadecadienoic acid,trans-9-octadecenoic acid, cis-9-octadecenoic acid, octadecanoic acid,tetradecanoic acid, pentadecanoic acid, heptadecanoic acid,22-hydroxydocosanoic acid, dihydroxyhexadecane,methyl-n,ω-dihydroxyoctadecanoate, coumaric acid, ferulic acid, otherC₁₆ or C₁₈ fatty acids, esters thereof, or any other <C₁₈ fatty acid (oresters thereof) included in a portion of a plant from which the plantextract composition is prepared. Furthermore, the plant extractcompositions described herein can be substantially free fromaccompanying plant-derived compounds (e.g., proteins, polysaccharides,phenols, lignans, aromatic acids, terpenoids, flavonoids, carotenoids,alkaloids, alcohols, alkanes, and aldehydes).

The relative concentrations of the various cutin monomers in the extractcan be dependent on the source plant matter or otherwise agriculturalproduct used to prepare the plant extract. In some embodiments, a plantor a portion of a plant can be selected such that the composition of thecutin monomers forming the cuticular layer in the portion of the plantyields the plant extract compositions described herein. In someembodiments, the plant matter can include agricultural waste productssuch as, for example, tomato peel, grape skins, apple peel, pepper peel,lemon peel, lemon leaf, lime peel, lime leaf, orange peel, orange leaf,orange fruit, clementine leaf, clementine fruit, mandarin leaf, mandarinfruit, pea seeds, grapefruit peel, grapefruit leaf, grapefruit seed,papaya peel, cherry fruits, cranberry skins, coffee cherries, grassclippings, or any other plants or portions of plants that can yield anyembodiment of the plant extract compositions described herein. Forexample, in some embodiments, the plant extract can be a tomato peelextract. In such embodiments, the tomato peel extract can include, forexample, about 65 wt % to about 85 wt % of a9(10),16-dihydroxyhexadecanoic acid (or the ester thereof), about 3 wt %to about 7 wt % of a 16-hydroxyhexadecanoic acid (or the ester thereof),about 1 wt % to about 4 wt % of a 9,10,18-trihydroxyoctadecanoic acid(or the ester thereof), and about 20 wt % to about 25 wt % residualfatty acids (or the esters thereof). For example, the tomato peelextract composition can include about 66 wt %, about 67 wt %, about 68wt %, about 69 wt %, about 70 wt %, about 71 wt %, about 72 wt %, about73 wt %, about 74 wt %, about 75 wt %, about 76 wt %, about 77 wt %,about 78 wt %, about 79 wt %, about 80 wt %, about 81 wt %, about 82 wt%, about 83 wt %, or about 84 wt % of the 9(10),16-dihydroxyhexadecanoicacid (or the ester thereof), inclusive of all ranges therebetween.Moreover, the tomato peel extract composition can include about 4 wt %,about 5 wt %, or about 6 wt % of the 16-hydroxyhexadecanoic acid (or theester thereof), inclusive of all ranges therebetween. The9,10,18-trihydroxyoctadecanoic acid (or the ester thereof) can be about2 wt %, or about 3 wt %, inclusive of all ranges therebetween, and theresidual fatty acids (or the esters thereof) can be about 21 wt %, about22 wt %, about 23 wt %, or about 24 wt%, inclusive of all rangestherebetween.

In some embodiments, the plant or portion of the plant selected forobtaining the plant extract composition can naturally include higherproportions of the C₁₆ and/or C₁₈ hydroxy fatty acids (or the estersthereof). For example, the portions of the plant selected for obtainingthe plant extract compositions described herein can include a higherproportion of the 9(10),16-dihydroxyhexadecanoic acid (or the esterthereof) such that the plant extract composition obtained from theportion of the plant has a concentration of the9(10),16-dihydroxyhexadecanoic acid (or the ester thereof) as describedherein (e.g., about 50 wt % to about 100 wt % of the first fraction,i.e., the C₁₆ hydroxy fatty acid (or the ester thereof) fraction). Insome embodiments, various combinations of different plant species and/orportions of plants (i.e., plant organs) can be selected to adjust therelative concentrations of the C₁₆ and/or C₁₈ hydroxy fatty acids (orthe esters thereof) obtained in the plant extract compositions describedherein. Dihydroxy fatty acids (e.g., 9(10),16-dihydroxyhexadecanoicacid) (or the esters thereof) and trihydroxy fatty acids (e.g.,9,10,18-trihydroxyoctadecanoic acid) (or the esters thereof) can formtightly bound networks with high crosslink density and low permeabilityrelative to monohydroxy fatty acids (or the esters thereof). Thus, theplant extract compositions described herein can include a relativeproportion of the dihydroxy fatty acids (or the esters thereof) and thetrihydroxy fatty acids (or the esters thereof), which can allow theplant extract compositions to be used in agricultural coatingformulations. Such coatings can be used for coating various portions ofthe plants such as, for example, plant stems, shoots, flowers, fruits,leaves, seeds, roots, etc., and preventing moisture loss, oxygendiffusion (which leads to oxidation), biotic stressors, surfacescratching or damage, etc. Such coatings can also be used to delayripening. Since the plant extract compositions are obtained from naturalsources, the plant extract compositions can be safe for humanconsumption. Furthermore, the plant extract compositions can bebiodegradable.

In some embodiments, a method of protecting a portion of a plant fromenvironmental and biotic stressors can include coating the portion ofthe plant with a coating including a plant extract composition. Theplant extract composition can include at least about 50 wt % to about100 wt % of C₁₆ hydroxy fatty acids (and/or esters thereof), at least 0wt % to about 35 wt % of C₁₈ hydroxy fatty acids (and/or estersthereof), and at least about 0 wt % to about 23 wt % of residual fattyacids (and/or esters thereof). The plant extract can be substantiallyfree of accompanying plant-derived compounds (e.g., proteins,polysaccharides, phenols, lignans, aromatic acids, terpenoids,flavonoids, carotenoids, alkaloids, alcohols, alkanes, and aldehydes).In some embodiments, the C₁₆ hydroxy fatty acids (or esters thereof) caninclude about 50 wt % to about 100 wt % of a9(10),16-dihydroxyhexadecanoic acid (or an ester thereof), about 2 wt %to about 27 wt % of a 16-hydroxyhexadecanoic acid (or an ester thereof),and 0 wt % to about 35 wt % of a 16-hydroxy-10-oxohexadecanoic acid (oran ester thereof). In some embodiments, the C₁₈ hydroxy fatty acids (oresters thereof) can include 0 wt % to about 100 wt % of a9,10,18-trihydroxyoctadecanoic acid (or an ester thereof), 0 wt % toabout 8 wt % of a 9(10),18-dihydroxyoctadecanoic acid (or an esterthereof), 0 wt % to about 9 wt % of a ω-hydroxyoctadecanoic acid (or anester thereof), and/or 0 wt % to about 33 wt % of aω-hydroxy-9,10-epoxy-octadecanoic acid (or an ester thereof). In someembodiments, the residual fatty acids (and/or fatty esters) can includefor example, hexadecanoic acid, dicarboxylic acids,9,10-dihydroxyhexadecane-1,16-dioic acid, 9,12-octadecadienoic acid,trans-9-octadecenoic acid, cis-9-octadecenoic acid, octadecanoic acid,tetradecanoic acid, pentadecanoic acid, heptadecanoic acid,22-hydroxydocosanoic acid, dihydroxyhexadecane,methyl-n,ω-dihydroxyoctadecanoate, coumaric acid, ferulic acid, otherC₁₆ or C₁₈ fatty acids, esters thereof, or any other <C₁₈ fatty acid (oresters thereof). The plant extract composition included in the coatingcan be extracted from a suitable plant or portion of a plant such as,for example, tomato skin, grape skin, lemon peel, lemon leaf, lime peel,lime leaf, orange peel, orange leaf, orange fruit, clementine leaf,clementine fruit, pea seed, grapefruit leaf, cranberry skins, and cherryfruit. Furthermore, the plant extract composition included in thecoating can be extracted using method 100 or any methods describedherein.

In some embodiments, the cutin-derived monomers and/or oligomersresulting from the depolymerization of cutin are functionalized (e.g.,modified, such as by conversion of the carboxylic acid to an ester oralcohol) prior to being applied to the surface of an agriculturalproduct to form a protective coating. Functionalizing the monomersand/or oligomers can in some cases impart desirable properties such asmodified solubility or hydrophobicity, which can result in improvedproperties of the subsequently formed protective coatings. Fatty acidscan be converted to esters by several chemical transformations, forexample via Fischer esterification with an alcohol and a catalyticamount of acid (e.g. methanol, ethanol, butanol, etc.) to form thecorresponding ester (methyl ester, ethyl ester, butyl ester). Forexample, 9(10),16-dihydroxyhexadecanoic acid from tomato skins can beconverted to ethyl 9(10),16-dihydroxyhexadecanoate by adding excessethanol and a catalytic amount of acid. As another example,9(10),16-dihydroxyhexadecanoic acid from tomato skins can be convertedto methyl 9(10),16-dihydroxyhexadecanoate by adding excess methanol anda catalytic amount of acid. Alternatively, fatty acids could beconverted to alcohols by using a reduction agent such as LiAlH₄. Forexample, 9(10),16-dihydroxyhexadecanoic acid from tomato skins can beconverted to hexadecane-1,7(8),16-triol with LiAlH₄.

Functionalization of Compounds

In some embodiments, functionalizing the cutin-derived monomers and/oroligomers includes carrying out one or more of the following reactions:

where R represents the fatty acid radical.

In some embodiments, the monomers and/or oligomers can be glycerated toform monoacylglyceride (e.g., 1-monoacylglyceride and/or2-monoacylglyceride) monomers and/or oligomers. For example, themonomers and/or oligomers can be functionalized or modified to one ormore compounds of Formula I:

wherein:

R is a 2-glyceryl optionally substituted with one or more C₁-C₆ alkyl orhydroxy;

R¹, R², R⁵, R⁶, R⁹, R¹⁰, R¹¹, R¹² and R¹³ are each independently —H,—OR¹⁴, —NR¹⁴R¹⁵, —SR¹⁴, halogen, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₂-C₆alkynyl, —C₃-C₇ cycloalkyl, —C₆-C₁₀ aryl, or 5 to 10-membered ringheteroaryl, wherein each —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₂-C₆ alkynyl,—C₃-C₇ cycloalkyl, —C₆-C₁₀ aryl, or 5 to 10-membered ring heteroaryl isoptionally substituted with —OR¹⁴, —NR¹⁴R¹⁵, —SR¹⁴ , or halogen;

R³, R⁴, R⁷ and R⁸ are each independently —H, —OR¹⁴, —NR¹⁴R¹⁵, —SR¹⁴,halogen, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₂-C₆ alkynyl, —C₃-C₇cycloalkyl, —C₆-C₁₀ aryl, or 5 to 10-membered ring heteroaryl whereineach —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₂-C₆ alkynyl, —C₃-C₇ cycloalkyl,—C₆-C₁₀ aryl, or 5 to 10-membered ring heteroaryl is optionallysubstituted with —OR¹⁴, —NR¹⁴R¹⁵, —SR¹⁴, or halogen; or

R³ and R⁴ can combine with the carbon atoms to which they are attachedto form a 3 to 6-membered ring, such as a cyclic ether;

R⁷ and R⁸ can combine with the carbon atoms to which they are attachedto form a 3 to 6-membered ring, such as a cyclic ether;

R¹⁴ and R¹⁵ are each independently —H, —C₁-C₆ alkyl, —C₁-C₆ alkenyl, or—C₁-C₆ alkynyl;

the symbol

represents an optionally single or cis or trans double bond;

n is an integer between 0 and 8;

m is an integer between 0 and 3;

q is an integer between 0 and 5; and

r is an integer between 0 and 8.

In some implementations, the monomers and/or oligomers are modified toform compounds of Formula I and/or compounds of Formula II:

wherein:

R′ is a 1-glyceryl optionally substituted with one or more C₁-C₆ alkylor hydroxy;

R¹, R², R⁵, R⁶, R⁹, R¹⁰, R¹¹, R¹² and R¹³ are independently —H, —OR¹⁴,—NR¹⁴R¹⁵, —SR¹⁴, halogen, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₂-C₆ alkynyl,—C₃-C₇ cycloalkyl, —C₆-C₁₀ aryl, or 5 to 10-membered ring heteroaryl,wherein each —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₂-C₆ alkynyl, —C₃-C₇cycloalkyl, —C₆-C₁₀ aryl, or 5 to 10-membered ring heteroaryl isoptionally substituted with —OR¹⁴, NR¹⁴R¹⁵, —SR¹⁴ , or halogen;

R³, R⁴, R⁷ and R⁸ are each independently —H, —OR¹⁴, —NR¹⁴R¹⁵, —SR¹⁴,halogen, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₂-C₆ alkynyl, —C₃-C₇cycloalkyl, —C₆-C₁₀ aryl, or 5 to 10-membered ring heteroaryl whereineach —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₂-C₆ alkynyl, —C₃-C₇ cycloalkyl,—C₆-C₁₀ aryl, or 5 to 10-membered ring heteroaryl is optionallysubstituted with —OR¹⁴, —NR¹⁴R¹⁵, SR¹⁴, or halogen; or

R³ and R⁴ can combine with the carbon atoms to which they are attachedto form a 3 to 6-membered ring, such as a cyclic ether;

R⁷ and R⁸ can combine with the carbon atoms to which they are attachedto form a 3 to 6-membered ring, such as a cyclic ether;

R¹⁴ and R¹⁵ are each independently —H, —C₁-C₆ alkyl, —C₁-C₆ alkenyl, or—C₁-C₆ alkynyl;

the symbol

represents an optionally single or cis or trans double bond;

n is an integer between 0 and 8;

m is an integer between 0 and 3;

q is an integer between 0 and 5; and

r is an integer between 0 and 8.

The modified/functionalized (e.g., esterized or glycerated) monomersand/or oligomers that make up the resulting plant extract compositioncan then be applied to the surface of an agricultural product to form aprotective coating. As seen in FIGS. 2-6 and their associateddescriptions below, protective coatings formed from compositions thatcomprise monoacylglycerides (e.g., compounds of Formula I and/or FormulaII, as described above) have been found to reduce the rate ofpost-harvest mass loss in a variety of agricultural products, and insome cases to reduce the rate of post-harvest molding and/or spoilage.

The compounds of Formula I and/or Formula II may be prepared by methodsknown in the art of organic synthesis as set forth in part by thefollowing synthetic schemes and examples. In the schemes describedbelow, it is well understood that protecting groups for sensitive orreactive groups are employed where necessary in accordance with generalprinciples or chemistry. Protective groups are manipulated according tostandard methods of organic synthesis (T. W. Greene and P. G. M. Wuts,“Protective Groups in Organic Synthesis”, Third edition, Wiley, New York1999). These groups are removed at a convenient stage of the compoundsynthesis using methods that are readily apparent to those skilled inthe art. The selection processes, as well as the reaction conditions andorder of their execution, shall be consistent with the preparation ofcompounds of Formula I.

Those skilled in the art will recognize if a stereocenter exists in thecompounds of Formula I and/or Formula II. Accordingly, the presentdisclosure includes both possible stereoisomers (unless specified in thesynthesis) and includes not only racemic compounds but the individualenantiomers and/or diastereomers as well. When a compound is desired asa single enantiomer or diastereomer, it may be obtained bystereospecific synthesis or by resolution of the final product or anyconvenient intermediate. Resolution of the final product, anintermediate, or a starting material may be affected by any suitablemethod known in the art. See, for example, “Stereochemistry of OrganicCompounds” by E. L. Eliel, S. H. Wilen, and L. N. Mander(Wiley-Interscience, 1994).

The compounds described herein may be made from commercially availablestarting materials or synthesized using known organic, inorganic, and/orenzymatic processes. In some embodiments, a compound of Formula I can beprepared from a corresponding acid or ester according to Scheme 1.

As shown in Scheme 1, compounds of Formula I can be prepared byprotecting any hydroxy groups that may be present in the acid. As shownabove in Scheme 1, hydroxy groups can be protected with a -TBS(tert-butyldimethylsilyl) protecting group. Esterification of theprotected acid with an appropriately protected glycerol derivative(e.g., 2-phenyl-1, 3-dioxan-5-ol) can be accomplished with the aid ofDMAP and DCC. Deprotection of the silyl protecting groups can beaccomplished with an appropriate agent such as hydrofluoric acid.Finally, the glycerol group can be deprotected by, for instance,hydrogenation.

A skilled artisan will understand the chemical synthesis procedures setforth herein can be adjusted as necessary. For instance, otherprotecting groups can be used to protect, e.g., the alcohol groups aswill be understood by one of skill in the art.

In some embodiments, the cutin-derived monomers, oligomers, andcombinations thereof comprise fatty acids, and the converting stepcomprises esterifying the fatty acids. In some embodiments, thecutin-derived monomers, oligomers, and combinations thereof compriseesters, and the converting step comprises transesterifying the esters.In some embodiments, the cutin-derived monomers, oligomers, andcombinations thereof comprise amides, and the converting step comprisestransesterifying the amides. In some embodiments, the converting stepcomprises treating the cutin-derived monomers, oligomers, andcombinations thereof with an appropriate alcohol and base or acid. Insome embodiments, the base is sodium hydroxide, lithium hydroxide,potassium hydroxide, sodium carbonate, lithium carbonate, or potassiumcarbonate. In some embodiments, the acid is hydrochloric, sulfuric, oracetic acid.

In some embodiments, compounds of the present disclosure can be preparedby direct esterification using a suitable solvent, e.g., methanol. Forinstance, an appropriate fatty acid (e.g., 10,16-dihydroxyhexadecanoicacid) can be converted to a corresponding ester (e.g., methyl 10,16-dihydroxyhexadecanoate) by treatment with an excess of a suitablesolvent (e.g., methanol). In some embodiments, the esterification takesplace in the presence of a suitable acid such as sulfuric acid. In someembodiments, the hydroxy groups on the fatty acid, if present areprotected using a suitable protecting group (e.g., -TBS), whereas insome embodiments the hydroxy groups on the fatty acid are not protected.

FIGS. 2-6 illustrate the effects of coating a variety of agriculturalproducts with plant extract compositions described herein. The coatingsformed on the agricultural products shown in FIGS. 2, 3, 5, and 6 wereeach formed from compositions that included a mixture of2-monoacylglyceride compounds (i.e., compounds of Formula I) and anadditive that included 1-monoacylglyceride compounds (i.e., compounds ofFormula II), wherein a mass ratio of the additive to the compound ofFormula I was in a range of 0.1 to 1. To form the coatings, the solidmixtures of the compositions were first fully dissolved in ethanol at aconcentration of 10 mg/mL to form a solution. The solution was thenapplied to the agricultural products either by spraying or dip coating,as detailed for each of the cases below. The agricultural products werethen dried on drying racks under ambient conditions (temperature in therange of 23-27 ° C., relative humidity in the range of 40%-55%) untilall of the solvent had evaporated, allowing the coatings to form overthe substrates. The resultant coatings each had a thickness in the rangeof 0.1 μm to 1 μm.

FIG. 2 shows the effects of mass loss over time observed in lemons overthe course of 3 weeks, both for uncoated lemons and for lemons that werecoated with the compositions described above. In order to form thecoatings, the lemons were placed in a bag, and the solution containingthe composition was poured into the bag. The bag was then sealed andlightly agitated until the entire surface of each lemon was wet. Thelemons were then removed from the bag and allowed to dry on drying racksunder ambient room conditions at a temperature in the range of about23-27° C. and relative humidity in the range of about 40-55%. The lemonswere held at these same temperature and relative humidity conditions forthe entire duration of the time they were tested. 202 is a highresolution photograph of an uncoated lemon immediately after beingpicked (Day 1), and 204 is a high resolution photograph of a lemonimmediately after being picked and coated on the same day. 212 and 214are photographs of the uncoated and coated lemons, respectively, takenon Day 22,21 days after photographs 202 and 204. In order to bettervisualize the cross-sectional area loss (which is directly related tomass loss), an overlay 222 of the outline of the untreated lemon on Day1 is shown around 212, and an overlay 224 of the outline of theuntreated lemon on Day 1 is shown around 214. The coated lemons had across sectional area greater than 90% of their original area (e.g.,greater than 92% of their original area), whereas the uncoated lemonshad a cross sectional area less than 80% of their original area, therebyindicating reduced mass loss observed for coated lemons as compared touncoated lemons stored under the same conditions.

FIG. 3 shows plots for both coated (302) and uncoated (304) lemonsindicating the reduction in cross sectional area as a function of timeover a period of 20 days. Specifically, on each day, high resolutionimages of each of the lemons were taken and analyzed with imageprocessing software (as in FIG. 2) to determine the ratio of the crosssectional area on the particular day to the initial cross sectional areaof the lemon. As seen in FIG. 3, after 20 days, the coated lemons had across sectional area greater than 90% of their original area (e.g.,greater than 92% of their original area), whereas the uncoated lemonshad a cross sectional area less than 80% of their original area, therebyindicating the reduced mass loss observed for coated lemons as comparedto uncoated lemons stored under the same conditions.

FIG. 4 shows high-resolution photographs of 4 coated and 4 uncoatedstrawberries over the course of 5 days. The coated strawberries werespray coated according to the following procedures. First, thestrawberries were placed on drying racks. A solution containing thecoating composition was placed in a spray bottle that generated a finemist spray. The spray head was held approximately six inches from thestrawberries, and the strawberries were sprayed and then allowed to dryon the drying racks. The strawberries were kept under ambient roomconditions at a temperature in the range of about 23-27° C. and relativehumidity in the range of about 40-55% while they dried and for theentire duration of the time they were tested. As seen, the uncoatedstrawberries began to exhibit fungal growth and discoloration by Day 3,and were mostly covered in fungus by Day 5. In contrast, the coatedstrawberries did not exhibit any visible fungal growth by Day 5 and werelargely similar in overall color and appearance on Day 1 and Day 5,indicating a reduction in molding and spoilage for coated strawberriesas compared to uncoated strawberries stored under the same conditions.

FIG. 5 shows plots of the percent mass loss over the course of 5 days inuncoated blueberries (502), blueberries coated using a solution of 10mg/mL of compounds dissolved in ethanol (504), and blueberries coatedusing a solution of 20 mg/mL of compounds dissolved in ethanol (506). Toform the coatings over the blueberries, the following dip coatingprocedures were used. Each blueberry was gently picked up with a set oftweezers and individually dipped in the solution for approximately 1second or less, after which the blueberry was placed on a drying rackand allowed to dry. The blueberries were kept under ambient roomconditions at a temperature in the range of about 23-27° C. and relativehumidity in the range of about 40-55% while they dried and for theentire duration of the time they were tested. Mass loss was measured bycarefully weighing the blueberries each day, where the reported percentmass loss was equal to the ratio of mass reduction to initial mass. Asshown, the percent mass loss for uncoated blueberries was almost 20%after 5 days, whereas the percent mass loss for blueberries coated withthe 10 mg/mL solution was less than 15% after 5 days, and the percentmass loss for blueberries coated with the 20 mg/mL solution was lessthan 10% after 5 days, thereby indicating reduced mass loss observed forcoated blueberries as compared to uncoated blueberries stored under thesame conditions.

FIG. 6 shows high-resolution photographs of the uncoated blueberries(602) and of the blueberries coated with the 10 mg/mL solution (604) atDay 5. The skins of the uncoated blueberries 602 were highly wrinkled asa result of mass loss of the blueberries, whereas the skins of thecoated blueberries remained very smooth.

In some embodiments, the depolymerization of the cutin and/or forming ofthe plant extract composition is carried out by a first party, while theapplication of the plant extract composition to an agricultural productto form a protective coating over the agricultural product is carriedout by a second party different from the first party. For example, amanufacturer of the plant extract compositions (i.e., a first party) canform the compositions by one or more of the methods described herein.The manufacturer can then sell or otherwise provide the resulting plantextract composition to a second party, for example a farmer, shipper,distributor, or retailer of produce, and the second party can apply thecomposition to one or more agricultural products to form a protectivecoating over the products. Alternatively, the manufacturer can sell orotherwise provide the resulting plant extract composition to anintermediary party, for example a wholesaler, who then sells orotherwise provides the plant extract composition to a second party suchas a farmer, shipper, distributor, or retailer of produce, and thesecond party can apply the composition to one or more agriculturalproducts to form a protective coating over the products.

In some cases where multiple parties are involved, the first party mayoptionally provide instructions or recommendations about the extractcomposition, either written or oral, indicating one or more of thefollowing: (i) that the composition is intended to be applied to aproduct for the purpose of coating or protecting the product, to extendthe life of the product, to reduce spoilage of the product, or to modifyor improve the aesthetic appearance of the product; (ii) conditionsand/or methods that are suitable for applying the compositions to thesurfaces of products; and/or (iii) potential benefits (e.g., extendedshelf life, reduced rate of mass loss, reduced rate of molding and/orspoilage, etc.) that can result from the application of the compositionto a product. While the instructions or recommendations may be suppliedby the first party directly with the plant extract composition (e.g., onpackaging in which the composition is sold or distributed), theinstructions or recommendations may alternatively be suppliedseparately, for example on a website owned or controlled by the firstparty, or in advertising or marketing material provided by or on behalfof the first party.

In view of the above, it is recognized that in some cases, a party thatmanufactures a plant extract composition according to one or moremethods described herein (i.e., a first party) may not directly form acoating over a product from the extract composition, but can insteaddirect (e.g., can instruct or request) a second party to form a coatingover a product from the extract composition. That is, even if the firstparty does not coat a product by the methods and compositions describedherein, the first party may still cause the plant extract composition tobe applied to the product to form a protective coating over the productby providing instructions or recommendations as described above.Accordingly, as used herein, the act of applying a plant extractcomposition to a product (e.g., a plant or agricultural product) alsoincludes directing or instructing another party to apply the plantextract composition to the product, or causing the plant extractcomposition to be applied to the product.

In some embodiments, the plant extract composition can be applieddirectly to a portion of a plant. In some embodiments, the plant extractcomposition can be heated to modify the physical and/or chemicalproperties of the composition prior to and/or during and/or after theapplication process. In some embodiments, the plant extract compositioncan be dissolved and/or suspended in a solvent, in aqueous solutions, orin a carrier liquid to form the coating. The solvent can include anypolar, non-polar, protic, or aprotic solvents, including anycombinations thereof. Examples of solvents that can be used to dissolvethe plant extract compositions described herein include water, methanol,ethanol, isopropanol, butanol, acetone, ethyl acetate, chloroform,acetonitrile, tetrahydrofuran, diethyl ether, methyl tent-butyl ether,any other suitable solvent or a combination thereof. Aqueous solutionsof such plant extract compositions can be suitable for coating onagricultural products, for example, forming a coating on theagricultural product. In some embodiments, the coatings can beconfigured to change the surface energy of the agricultural product.Various properties of coatings described herein can be adjusted bytuning the crosslink density of the coating, its thickness, or itscomposition. This can, for example, be used to control the ripening ofpostharvest fruit or produce. For example, plant extract compositioncoatings that primarily include bifunctional or polyfunctional cutinmonomer units can, for example, have higher crosslink densities thanthose that include monofunctional or bifunctional cutin monomer units.Thus, the plant extract composition coatings that primarily includebifunctional or polyfunctional cutin monomer units can result in slowerrates of ripening.

In some embodiments, an acid or a base can be added to the coatingformulation to achieve a desired pH suitable for coating the plantextract composition coating on the agricultural product. In someembodiments, additives such as, for example, surfactants, emulsifiers,thickening agents, nonionic polymers, waxes, or salts can be included inthe coating formulation. In some embodiments, weak acids, ions, ornon-reactive molecules can be included in the coating formulation tocontrol or adjust the properties of the resulting films or coatings. Insome embodiments, pH stabilizers or modifiers can also be included inthe coating formulation. In some embodiments, the coating formulationcan include additional materials that are also transported to thesurface with the coating, or are deposited separately and aresubsequently encapsulated by the coating (i.e., the coating is formed atleast partially around the additional material), or are depositedseparately and are subsequently supported by the coating (i.e., theadditional material is anchored to the external surface of the coating).Examples of such additional materials can include cells, biologicalsignaling molecules, vitamins, minerals, pigments, aromas, enzymes,catalysts, antifungals, antimicrobials, and/or time-released drugs. Theadditional materials can be non-reactive with surface of theagricultural product and/or coating, and/or reactive with the surfaceand/or coating.

In some embodiments, the coating can include an additive configured, forexample, to modify the viscosity, vapor pressure, surface tension, orsolubility of the coating. In some embodiments, the additive can beconfigured to increase the chemical stability of the coating. Forexample, the additive can be an antioxidant configured to inhibitoxidation of the coating. In some embodiments the additive can be addedto reduce or increase the melting temperature or the glass-transitiontemperature of the coating. In some embodiments, the additive can beconfigured to reduce the diffusivity of water vapor, oxygen, CO₂, orethylene through the coating or enable the coating to absorb more ultraviolet (UV) light, for example to protect the agricultural product(e.g., any of the products described herein). In some embodiments, theadditive can be configured to provide an intentional odor, for example afragrance (e.g., smell of flowers, fruits, plants, freshness, scents,etc.). In some embodiments, the additive can be configured to providecolor and can include, for example, a dye or a US Food and DrugAdministration (FDA) approved color additive. In some embodiments, theadditives can include sweeteners, color additives, flavors, spices,flavor enhancers, fat replacers, and components of formulations used toreplace fats, nutrients, emulsifiers, bulking agents, cleansing agents,stabilizers, emulsion stabilizers, thickeners, flavor or fragrance, aningredient of a flavor or fragrance, binders, texturizers, humectants,pH control agents, acidulants, leavening agents, anti-caking agents,antifungal agents, antimicrobial agents, antioxidants, and/or UVfilters. In some embodiments, the coating can include a photoinitiator,which can initiate crosslinking of the coating on exposure to anappropriate light source, for example, UV light.

In some embodiments, any of the plant extract composition coatingsdescribed herein can be flavorless or have high flavor thresholds, e.g.above 500 ppm, and can be odorless or have a high odor threshold. Insome embodiments, the materials included in any of the coatingsdescribed herein can be substantially transparent. For example, theplant extract composition, the solvent, and/or any other additivesincluded in the coating can be selected so that they have substantiallythe same or similar indices of refraction. By matching their indices ofrefraction, they may be optically matched to reduce light scattering andimprove light transmission. For example, by utilizing materials thathave similar indices of refraction and have a clear, transparentproperty, a coating having substantially transparent characteristics canbe formed.

Any of the coatings described herein can be disposed on the externalsurface of an agricultural product using any suitable means. Forexample, in some embodiments, the agricultural product can be dip-coatedin a bath of the coating formulation (e.g., an aqueous or mixedaqueous—organic or organic solution of the plant extract composition).The deposited coating can form a thin layer on the surface of anagricultural product, which can protect the agricultural product frombiotic stressors, water loss, and/or oxidation. In some embodiments, thedeposited coating can have a thickness of less than about 1500 nm, suchthat the coating is transparent to the naked eye. For example, thedeposited coating can have a thickness of about 10 nm, about 20 nm,about 30 nm, about 40 nm, about 50 nm, about 100 nm, about 150 nm, about200 nm, about 250 nm, about 300 nm, about 350 nm, about 400 nm, about450 nm, about 500 nm, about 550 nm, about 600 nm, about 650 nm, about700 nm, about 750 nm, about 800 nm, about 850 nm, about 900 nm, about950 nm, 1,000 nm, about 1,100 nm, about 1,200 nm, about 1,300 nm, about1,400 nm, or about 1,500 nm, inclusive of all ranges therebetween. Insome embodiments, the deposited coating can be uniformly deposited overthe agricultural product and free of defects and/or pinholes. In someembodiments, the dip-coating process can include sequential coating ofthe agricultural product in baths of coating precursors that can undergoself-assembly or covalent bonding on the agricultural product to formthe coating. In some embodiments, the coating can be deposited onagricultural products by passing the agricultural products under astream of the coating formulation (e.g., a waterfall of the liquidcoating). For example, the agricultural products can be disposed on aconveyor that passes through the stream of the coating formulation. Insome embodiments, the coating can be misted, vapor- or dryvapor-deposited on the surface of the agricultural product. In someembodiments, the coating can be configured to be fixed on the surface ofthe agricultural product by UV crosslinking or by exposure to a reactivegas, for example, oxygen.

In some embodiments, the plant extract composition coating can bespray-coated on the agricultural products. Commercially availablesprayers can be used for spraying the coating or precursors of thecoating onto the agricultural product. In some embodiments, the coatingformulation can be electrically charged in the sprayer beforespray-coating on to the agricultural product, such that the depositedcoating electrostatically and/or covalently bonds to the exteriorsurface of the agricultural product.

The coating can be configured to prevent water or otherwise moistureloss from the coated portion of the plant, delay ripening, and/orprevent oxygen diffusion into the coated portion of the plant, forexample, to reduce oxidation of the coated portion of the plant. Thecoating can also protect the coated portion of the plant against bioticstressors, such as, for example, bacteria, fungi, viruses, and/or peststhat can infest and decompose the coated portion of the plant. Sincebacteria, fungi and pests all identify food sources via recognition ofspecific molecules on the surface of the agricultural product, coatingthe agricultural products with the coating containing the plant extractcompositions can deposit molecularly contrasting molecules on thesurface of the portion of the plant, which can render the agriculturalproducts unrecognizable. Furthermore, the coating can also alter thephysical and/or chemical environment of the surface of the agriculturalproduct making the surface unfavorable for bacteria, fungi or pests togrow. The coating can also be formulated to protect the surface of theportion of the plant from abrasion, bruising, or otherwise mechanicaldamage, and/or protect the portion of the plant from photodegradation.The portion of the plant can include, for example, a leaf, a stem, ashoot, a flower, a fruit, a root, etc. In some embodiments, the coatingcan be used to coat fruits and, for example, delay ripening of thefruit.

Application of Coatings to Produce

Any of the coatings described herein can be disposed on the externalsurface of an agricultural product using any suitable means. Forexample, in some embodiments, the agricultural product can be dip coatedin a bath of the coating (e.g., an aqueous solution of hydrogen-bondingorganic molecules). The coating can form a thin layer on the surface ofagricultural product, which can protect the agricultural product frombiotic stressors, water loss, and/or oxidation. In some embodiments, thedeposited coating can have a thickness of less than about 2 microns, forexample less than 1 micron, less than 900 nm, less than 800 nm, lessthan 700 nm, less than 600 nm, less than 500 nm, less than 400 nm, lessthan 300 nm, less than 200 nm, or less than 100 nm, such that thecoating is transparent to the naked eye. For example, the depositedcoating can have a thickness of about 50 nm, 60 nm, 70 nm, 80 nm, 90 nm,100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 200 nm, 250 nm, 300 nm,350 nm, 400 nm, 450 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, or about1,000 nm inclusive of all ranges therebetween. The deposited coating canhave a high degree of crystallinity to decrease permeability, such thatthe coating is conformally deposited over the agricultural product andis free of defects and/or pinholes. In some embodiments, the dip coatingprocess can include sequential coating of the agricultural product inbaths of precursors that can undergo self-assembly or covalent bondingon the agricultural product to form the coating. In some embodiments,the coatings can be deposited on agricultural products by passing theagricultural products under a stream of the coating (e.g., a waterfallof the liquid coating). For example, the agricultural products can bedisposed on a conveyor that passes through the stream of the coating. Insome embodiments, the coating can be vapor deposited on the surface ofthe agricultural product. In some embodiments, the coating can beformulated to be fixed on the surface of the agricultural product by UVcross-linking or by exposure to a reactive gas, for example, oxygen. Insome embodiments, the coating can be applied in the field before harvestas an alternative to pesticides.

In some embodiments, the functionalized cutin-derived monomers,oligomers, or combinations thereof are dissolved in a suitable solvent(e.g., water, ethanol, or a combination thereof) prior to coating theagricultural product.

In some embodiments the process of disposing the composition on theagricultural product comprises dip-coating the agricultural product in asolution comprising the plurality of cutin-derived monomers, oligomers,or combinations thereof. In some embodiments the process of disposingthe composition on the agricultural product comprises spray-coating theproduce with a solution comprising the plurality of cutin-derivedmonomers, oligomers, or combinations thereof.

In some embodiments, any of the coatings can be spray coated on theagricultural products. Commercially available sprayers can be used forspraying the coating or precursors of the coating onto the agriculturalproduct. In some embodiments, the coatings can be electrically chargedin the sprayer before spray coating on the agricultural product, suchthat the coating covalently bonds to the exterior surface of theagricultural product.

In some embodiments, the coating can be deposited on the agriculturalproduct such that the coating is unbound to the surface of theagricultural product. In some embodiments, one or more components of thecoating, for example, the hydrogen-bonding organic molecule, can becovalently (or hydrogen) bonded to at least a portion of the surface ofthe agricultural product. This can result in improved coating propertiessuch as, for example, higher durability, tighter control of coatingpermeability and thickness. In some embodiments, multiple layers of thecoating can be deposited on the surface of agricultural product toachieve a durable coating.

In some embodiments the plant extract composition comprises a pluralityof cutin-derived monomers, oligomers, or combinations thereof and asolvent selected from water, ethanol, and combinations thereof. In someembodiments the method causes one or more of the cutin monomers tocross-link on the surface of the produce.

Any of the coatings described herein can be used to protect anyagricultural product. In some embodiments, the coating can be coated onan edible agricultural product, for example, fruits, vegetables, edibleseeds and nuts, herbs, spices, produce, meat, eggs, dairy products,seafood, grains, or any other consumable item. In such embodiments, thecoating can include components that are non-toxic and safe forconsumption by humans and/or animals. For example, the coating caninclude components that are U.S. Food and Drug Administration (FDA)approved direct or indirect food additives, FDA approved food contactsubstances, satisfy FDA regulatory requirements to be used as a foodadditive or food contact substance, and/or is an FDA GenerallyRecognized as Safe (GRAS) material. Examples of such materials can befound within the FDA Code of Federal Regulations Title 21, located at“http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm”,the entire contents of which are hereby incorporated by referenceherein. In some embodiments, the components of the coating can include adietary supplement or ingredient of a dietary supplement. The componentsof the coating can also include an FDA approved food additive or coloradditive. In some embodiments, the coating can include components thatare naturally derived, as described herein. In some embodiments, thecoating can be flavorless or have a high flavor threshold of below 500ppm, are odorless or have a high odor threshold, and/or aresubstantially transparent. In some embodiments, the coating can beconfigured to be washed off an edible agricultural product, for example,with water.

In some embodiments, the coating described herein can be coated on aninedible agricultural product. Such inedible agricultural products caninclude, for example, inedible flowers, seeds, shoots, stems, leaves,whole plants, and the likes. In such embodiments, the coating caninclude components that are non-toxic but the threshold level fornon-toxicity can be higher than that prescribed for edible products. Insuch embodiments, the coating can include an FDA approved food contactsubstance, an FDA approved food additive, or an FDA approved drugingredient, for example, any ingredient included in the FDA's databaseof approved drugs, which can be found at“http://www.accessdata.fda.gov/scripts/cder/drugsatfda/index.cfm”, theentire contents of which are hereby incorporated herein by reference. Insome embodiments, the coating can include materials that satisfy FDArequirements to be used in drugs or are listed within the FDA's NationalDrug Discovery Code Directory,“http://www.accessdata.fda.gov/scripts/cder/ndc/default.cfm”, the entirecontents of which are hereby incorporated herein by reference. In someembodiments, the materials can include inactive drug ingredients of anapproved drug product as listed within the FDA's database,“http://www.accessdata.fda.gov/scripts/cder/ndc/default.cfm”, the entirecontents of which are hereby incorporated herein by reference.

Embodiments of the coatings described herein provide several advantages,including, for example: (1) the coatings can protect the agriculturalproducts from biotic stressors, i.e. bacteria, viruses, fungi, or pests;(2) the coatings can prevent evaporation of water and/or diffusion ofoxygen; (3) coating can help extend the shelf life of agriculturalproducts, for example, post-harvest produce, without refrigeration; (4)the coatings can introduce mechanical stability to the surface of theagricultural products eliminating the need for expensive packagingdesigned to prevent the types of bruising which accelerate spoilage; (5)use of agricultural waste materials to obtain the coatings can helpeliminate the breeding environments of bacteria, fungi, and pests; (6)the coatings can be used in place of pesticides to protect plants,thereby minimizing the harmful impact of pesticides to human health andthe environment; (7) the coatings can be naturally derived and hence,safe for human consumption. Since the components of the coatingsdescribed herein can in some embodiments be obtained from agriculturalwaste, such coatings can be made at a relatively low cost. Therefore,the coatings can be particularly suited for small scale farmers, forexample, by reducing the cost required to protect crops from pesticidesand reducing post-harvest losses of agricultural products due todecomposition by biotic and/or environmental stressors.

The following examples describe plant extract compositions obtainedusing the methods described herein. These examples are only forillustrative purposes and are not meant to limit the scope of thepresent disclosure.

EXAMPLES

All reagents and solvents were purchased and used without furtherpurification unless specified. Palmitic acid (98%) was purchased fromSigma-Aldrich. p-TsOH and MTBE were purchased from Alfa-Aesar. Toluene,Et₂O, and EtOAc were purchased from VWR. Lipozyme® TL IM lipase waspurchased from Novozymes. 10 wt % Pd/C was purchased from StremChemicals and used as received. All reactions were carried out under anatmosphere of air with non-dried solvents unless otherwise stated.Yields refer to chromatographically and spectroscopically (¹H NMR)homogeneous materials, unless otherwise stated. Reactions were monitoredby thin layer chromatography (TLC) carried out on 0.25 mm E. Mercksilica gel plates (60 Å, F-254) using UV light as the visualizing agentand an acidic mixture of anisaldehyde, ceric ammonium molybdate, orbasic aqueous potassium permanganate (KMnO₄), and heat as developingagents. NMR spectra were recorded on a Bruker Avance 500 MHz and/orVarian VNMRs 600 MHz instruments and calibrated using residualun-deuterated solvent as an internal reference (CHCl₃@7.26 ppm ¹H NMR,77.16 ppm ¹³C NMR). The following abbreviations (or combinationsthereof) were used to explain the multiplicities: s=singlet, d=doublet,t=triplet, q=quartet, m=multiplet, br=broad. Mass spectra (MS) wererecorded on a time of-flight mass spectrometer by electrosprayionization (ESI) or field desorption (FD) at the UC Santa Barbara massspectrometry facility. 1,3-bis(benzyloxy)propan-2-ol was synthesizedaccording to the procedure of Nemoto et al. (J. Org. Chem., 1992, 57, p.435).

The following abbreviations are used in the following examples andthroughout the specification:

-   DCC=N,N′-Dicyclohexylcarbodiimide-   DCM=dichloromethane-   DMAP=Dimethylamino pyridine-   DMF=N,N-dimethylformamide-   MBTE=^(t)BME =tert-butylmethyl ether-   p-TsOH=para toluenesulfonic acid-   TBS=TBDP=tert-butyldimethyl silyl

Example 1: Plant Extract Composition Obtained from Tomato Skin/Peel—I

Whole tomatoes were cut in to halves or quarters and boiled in wateruntil the skins were visibly loosened. The skins were mechanicallyseparated from the tomato flesh using a food mill to remove as much ofthe fruit flesh and seeds from the peels as possible. The separatedpeels were then heated in an aqueous solution of about 16 grams perliter ammonium oxalate and about 4 grams per liter oxalic acid at 75degrees Celsius for about 16 hours to disrupt the pectinaceous gluepresent between the cuticular layer and the underlying tomato flesh. Theremaining peel including the cutin was isolated by filtration, rinsedwith water, and oven-dried at 65 degrees Celsius to remove residualmoisture prior to depolymerization. The skin (i.e., the cutin-containingportion) was depolymerized in a methanolic solution including astoichiometric excess of potassium hydroxide (relative to tomato skin)at about 65 degrees Celsius for about 24 hours. The resulting solutionwas filtered to remove any leftover solids and the filtrate wascollected. Any excess solvent was removed from the filtered solution byrotary evaporation. The crude solid was redissolved in distilled waterand chilled in an ice bath, and the pH of the resulting solution wasadjusted to about 2 by adding aqueous HCl to the solution. Thedepolymerized multifunctional fatty acid monomers and oligomers of thecutin were solidified by precipitating from solution or by evaporationand the monomers were isolated by filtration to yield the tomato peelextract. The tomato peel extract was purified using columnchromatography using a 3:1 volumetric ratio of hexane:acetone. Thetomato peel extract included 70 wt % 10,16-dihydroxyhexadecanoic acid, 5wt % 16-hydroxyhexadecanoic acid, 3 wt % 9,10,18-trihydroxyoctadecanoicacid, and 22 wt % residual fatty acids and other plant by-products.

Example 2: Plant Extract Composition Obtained from Tomato Skin/Peel—II

Dried tomato peels and pomace obtained directly from an industrialtomato processing facility were ground to a fine powder using anelectric grinder and then directly subjected to depolymerization. Thewaste (i.e., cutin-containing peels and pomace) was depolymerized in amethanolic solution including a stoichiometric excess of potassiumhydroxide (relative to tomato waste) at about 65 degrees Celsius forabout 24 hours. The resulting solution was filtered to remove anyleftover solids and the filtrate was collected. Any excess solvent wasremoved from the filtered solution by rotary evaporation. The crudesolid was redissolved in distilled water and chilled in an ice bath, andthe pH of the resulting solution was adjusted to about 2 by addingaqueous HCl to the solution. The depolymerized multifunctional fattyacid monomers and oligomers of the cutin were solidified byprecipitating from solution or by evaporation and the monomers were andisolated by filtration to yield the crude tomato peel extract. The driedcrude tomato peel extract was dry-loaded onto Celite and subjected toSoxhlet extraction with acetonitrile for 1 day. The solution in thesolvent reservoir below the Soxhlet apparatus was collected and excesssolvent was removed by rotary evaporator to yield a purified,resolidified, tomato peel extract.

Example 3: Plant Extract Composition Obtained from Cranberry

Cranberries were diced and boiled in water until their skins werevisibly loosened. The aqueous mixture containing berry flesh and berryskins was then subjected to sonication to mechanically detach the berryflesh from the skins. The mixture was sonicated for 5-10 minutes at atime. Sonication was applied in alternation with filtration of theaqueous berry mixture through a coarse filter whereby the filter cakewas washed with distilled water to eliminate fine debris and isolate afilter cake increasingly enriched in berry skin. The sonication andfiltration steps were continued in alternation until the majority of theberry flesh was removed from the berry skin-enriched final filter cake.After oven-drying at 65 degrees Celsius to remove residual moisture, thecranberry skins were next subjected to a first Soxhlet extraction withchloroform for 2 days followed by a second Soxhlet extraction withmethanol for 1 day. The cutin-rich skins were subsequently depolymerizedin a methanolic solution including a stoichiometric excess of potassiumhydroxide (relative to cranberry skin) at about 65 degrees Celsius forabout 24 hours. The resulting solution was filtered to remove anyleftover solids and the filtrate was collected. Any excess solvent wasremoved from the filtered solution by rotary evaporation. The crudesolid was redissolved in distilled water and chilled in an ice bath, andthe pH of the resulting solution was adjusted to about 2 by addingaqueous HCl to the solution. The depolymerized multifunctional fattyacid monomers and oligomers of the cranberry cutin were solidified byprecipitating from solution or by evaporation and the monomers wereisolated by filtration to yield the cranberry skin extract. Thecranberry extract was purified using column chromatography using a 3:1volumetric ratio of hexane:acetone.

Example 4: Plant Extract Composition Obtained from Grape Berry

White grape pressings leftover from winemaking were boiled in wateruntil their skins were visibly loosened. The aqueous mixture containinggrape flesh and grape skins was then subjected to sonication tomechanically detach the grape flesh from the grape skins. The mixturewas sonicated for 5-10 minutes at a time. Sonication was applied inalternation with filtration of the aqueous berry mixture through acoarse filter whereby the filter cake was washed with distilled water toeliminate seeds and fine debris and isolate a filter cake increasinglyenriched in grape skin. The sonication and filtration steps werecontinued in alternation until approximately half of the berry flesh(volumetrically) was removed from the final grape skin-enriched filtercake. The filter cake was then subjected to enzymatic treatment todetach any remaining grape flesh from the grape skins. The filter cakewas dispersed into an aqueous buffer solution (0.2 mM acetate, pH 4)containing 0.1 wt % cellulase and 0.1 wt % pectinase and shaken on anorbital shaker at 40 degrees Celsius and 200 rpm for 24 hours. Theaqueous mixture was then filtered through a coarse filter and washedwith distilled water to obtain a filter cake enriched withcutin-containing grape skin. After oven-drying at 65 degrees Celsius toremove residual moisture, the grape skins were next subjected to a firstSoxhlet extraction with chloroform for 2 days followed by a secondSoxhlet extraction with methanol for 1 day. The cutin-rich skins weresubsequently depolymerized in a methanolic solution including astoichiometric excess of potassium hydroxide (relative to grape skin) atabout 65 degrees Celsius for about 24 hours. The resulting solution wasfiltered to remove any leftover solids and the filtrate was collected.Any excess solvent was removed from the filtered solution by rotaryevaporation. The crude solid was redissolved in distilled water andchilled in an ice bath, and the pH of the resulting solution wasadjusted to about 2 by adding aqueous HCl to the solution. Thedepolymerized multifunctional fatty acid monomers and oligomers of thecutin were solidified by precipitating from solution or by evaporationand the monomers were isolated by filtration to yield the grape skinextract. The grape skin extract was purified using column chromatographyusing a 3:1 volumetric ratio of hexane:acetone.

Example 5: Plant Extract Composition Obtained from Tomato Skin/Peel andAgricultural Coating Formed Thereof

Dried tomato peels or pomace obtained directly from an industrial tomatoprocessing facility were ground to a fine powder using an electricgrinder and then directly subjected to depolymerization. Thecutin-containing peels or pomace were depolymerized in two batches of anethanolic mixture (e.g., a first solvent) that were each substantiallyfree of water (e.g., less than 5% water by mass). The ethanolic mixturewas formed by adding sodium metal to ethanol under inert conditions,generating sodium ethoxide within the mixture. The cutin-containingpeels and pomace were then added to the first and second batches of theethanolic mixture. The resulting solutions were heated to and held atreflux under inert atmosphere. The reaction proceeded for 24 hours forthe first batch and 48 hours for the second batch, resulting inrespective first and second solutions which each included crude sodium10,16-dihydroxyhexadecanoate.

The solutions were each then cooled to room temperature and acidified toa pH of about 7 by addition of 3M HCl. The acidified solutions were thenfiltered to remove any insoluble salts, unreacted material, and otherimpurities, and the filtrates were evaporated to dryness. The resultingmaterials were each then re-dissolved in methanol and absorbed onto 3×their respective mass of Celite by evaporating the solvent. The adsorbedmixtures were then Soxhlet extracted sequentially by heptane, ethylacetate, and methanol. Separation of the 10,16-dihydroxypalmitic acidfrom other species and impurities within the adsorbed mixtures wasmonitored by UPLC-MS (ESI+). The 10,16-dihydroxypalmitic acidpreferentially partitioned into the ethyl acetate, with less polarimpurities extracting from the Celite into the heptane wash, and themore polar impurities extracting into the methanol wash. The obtainedextract composition from each of the two batches was a yellow tocolorless free flowing powder after evaporation of the solvent. Thepowders from each of the two batches were then combined into a singlecomposition. FIG. 7 shows purity data, obtained using mass spectrometryand FIG. 8 shows elemental analysis, of the resulting powder, indicatinga high level of purity.

A first portion of the 10,16-dihydroxypalmitic acid of the compositionwas then functionalized to form ethyl 10,16-dihydroxypalmitate, while asecond portion was functionalized to form 2,3-dihydroxypropyl10,16-dihydroxypalmitate (i.e., the 1-monoacylglycerideester of10,16-dihydroxypalmitic acid). The ethyl 10,16-dihydroxypalmitate wasprepared by Fisher esterification of the 10,16-dihydroxypalmitic acid inethanol using sulfuric acid as a catalyst. The 2,3-dihydroxypropyl10,16-dihydroxypalmitate was prepared by reaction of the10,16-dihydroxypalmitic acid with glycidol under basic catalysis.

The ethyl 10,16-dihydroxypalmitate was then dissolved in substantiallypure ethanol at a concentration of 67 mg/mL to form a first extractcomposition, and the 2,3-dihydroxypropyl 10,16-dihydroxypalmitate wasdissolved in substantially pure ethanol at a concentration of 37 mg/mLto form a second extract composition. Finally, agricultural coatingswere formed from the first extract composition on a first set of keylimes and from the second extract composition on a second set of keylimes using the following process. The first and second extractcompositions were poured into respective first and second plastic bags.10 key limes were then placed in each bag, and the bags were eachagitated for about 10 seconds to ensure that the extract compositionscovered the entirety of each key lime. The key limes were then removedand placed on dryings racks, and the solvent allowed to evaporate. Thisresulted in about 20 mg of the ethyl 10,16-dihydroxypalmitate extractbeing deposited over each key lime of the first set of key limes, andabout 11 mg of the 2,3-dihydroxypropyl 10,16-dihydroxypalmitate extractbeing deposited over each key lime of the second set of key limes.

FIGS. 9-11 are high resolution photographs of untreated key limes. FIG.9 shows untreated key limes 900. FIG. 10 shows key limes coated with theplant extracts of the first extract composition (1000). FIG. 11 showskey limes coated with the plant extracts of the second extractcomposition (1100). Each photograph was taken approximately 24 hoursafter the coatings were formed. The coatings formed from both extractcompositions were translucent and substantially undetectable to thehuman eye. However, the coating formed from the second extractcomposition reduced the glossiness of the key limes, whereas theglossiness of key limes coated with the first extract composition wasmaintained.

Example 6: Synthesis of 1,3-dihydroxypropan-2-yl Palmitate

Step 1. 1,3-bis(benzyloxy)propan-2-yl Palmitate

70.62 g (275.34 mmole) of palmitic acid, 5.24 g (27.54 mmole) of p-TsOH,75 g (275.34 mmole) of 1,3-bis(benzyloxy)propan-2-ol, and 622 mL oftoluene were charged into a round bottom flask equipped with a Tefloncoated magnetic stir bar. A Dean-Stark Head and condenser were attachedto the flask and a positive flow of N₂ was initiated. The flask washeated to reflux in a heating mantle while the reaction mixture wasstirred vigorously until the amount of water collected (˜5 mL) in theDean-Stark Head indicated full ester conversion (˜8 hr). The flask wasallowed to cool down to room temperature and the reaction mixture waspoured into a separatory funnel containing 75 mL of a saturated aqueoussolution of NaCO₃ and 75 mL of brine. The toluene fraction was collectedand the aqueous layer was extracted with 125 mL of Et₂O. The organiclayers were combined and washed with 100 mL of brine, dried over MgSO₄,filtered and concentrated in vacuo. The crude colorless oil was driedunder high vacuum providing (135.6 g, 265.49 mmole, crude yield=96.4%)of 1,3-bis(benzyloxy)propan-2-yl palmitate.

HRMS (ESI-TOF) (m/z): calcd. for C₃₃H₅₀O₄Na, [M+Na]⁺, 533.3607; found,533.3588;

¹H NMR (600 MHz, CDCl₃): δ 7.41-7.28 (m, 10H), 5.28 (p, J=5.0 Hz, 1H),4.59 (d, J=12.1 Hz, 2H), 4.54 (d, J=12.1 Hz, 2H), 3.68 (d, J=5.2 Hz,4H), 2.37 (t, J=7.5 Hz, 2H), 1.66 (p, J=7.4 Hz, 2H), 1.41-1.15 (m, 24H),0.92 (t, J=7.0 Hz, 3H) ppm.

¹³C NMR (151 MHz, CDCl₃): δ 173.37, 138.09, 128.43, 127.72, 127.66,73.31, 71.30, 68.81, 34.53, 32.03, 29.80, 29.79, 29.76, 29.72, 29.57,29.47, 29.40, 29.20, 25.10, 22.79, 14.23 ppm.

Step 2. 1,3-dihydroxypropan-2-yl Palmitate

7.66 g (15.00 mmoles) of 1,3-bis(benzyloxy)propan-2-yl palmitate, 79.8mg (0.75 mmole) of 10 wt % Pd/C and 100 mL of EtOAc were charged to a 3neck round bottom flask equipped with a Teflon coated magnetic stir bar.A cold finger, with a bubbler filled with oil attached to it, and abubbling stone connected to a 1:4 mixture of H₂/N₂ gas tank were affixedto the flask. H₂/N₂ was bubbled at 1.2 LPM into the flask until thedisappearance of both starting material and mono-deprotected substrateas determined by TLC (˜60 min). Once complete, the reaction mixture wasfiltered through a plug of Celite, which was then washed with 100 mL ofEtOAc. The filtrate was placed in a refrigerator at 4° C. for 24 hrs.The precipitate from the filtrate (white and transparent needles) wasfiltered and dried under high vacuum yielding (2.124 g, 6.427 mmole,yield=42.8%) of 1,3-dihydroxypropan-2-yl palmitate.

HRMS (FD-TOF) (m/z): calcd. for C₁₉H₃₈O₄, 330.2770; found, 330.2757;

¹H NMR (600 MHz, CDCl₃): δ4.93 (p, J=4.7 Hz, 1H), 3.84 (t, J=5.0 Hz,4H), 2.37 (t, J=7.6 Hz, 2H), 2.03 (t, J =6.0 Hz, 2H), 1.64 (p, J =7.6Hz, 2H), 1.38-1.17 (m, 26H), 0.88 (t, J =7.0 Hz, 3H) ppm.

¹³C NMR (151 MHz, CDCl₃): δ174.22, 75.21, 62.73, 34.51, 32.08, 29.84,29.83, 29.81, 29.80, 29.75, 29.61, 29.51, 29.41, 29.26, 25.13, 22.85,14.27 ppm.

Example 7: Synthesis of 1,3-dihydroxypropan-2-yl Palmitate by EnzymeCatalysis

3.66 g (4.50 mmoles) of tripalmitin, 7.26 mg of Lipozyme® TL-IM lipase,2.65 mL of EtOH, and 363 mL of MTBE were charged to a round bottom flaskequipped with a Teflon coated magnetic stir bar. The reaction mixturewas stirred for 15 min at room temperature, filtered, and concentratedin vacuo. 15 mL of hexanes was added to the crude product and theproduct/hexanes mixture was stored in a refrigerator at 4° C. for 24hrs. The crude mixture was filtered, washed with 30 mL of cold hexanes,and dried under high vacuum yielding 1.256 g (3.8 mmole, yield=84.4%) of1,3-dihydroxypropan-2-yl palmitate. (Note: yield is based on total massbeing from 1,3-dihydroxypropan-2-yl palmitate, however it contains 12.16mole % (20 wt %) of diacylglycerol palmitate.)

HRMS (FD-TOF) (m/z): calcd. for C₁₉H38O₄, 330.2770; found, 330.2757;

¹H NMR (600 MHz, CDCl₃): δ 4.93 (p, J=4.7 Hz, 1H), 3.84 (t, J=5.0 Hz,4H), 2.37 (t, J=7.6 Hz, 2H), 2.03 (t, J=6.0 Hz, 2H), 1.64 (p, J=7.6 Hz,2H), 1.38-1.17 (m, 26H), 0.88 (t, J=7.0 Hz, 3H) ppm.

¹³C NMR (151 MHz, CDCl₃): δ 174.22, 75.21, 62.73, 34.51, 32.08, 29.84,29.83, 29.81, 29.80, 29.75, 29.61, 29.51, 29.41, 29.26, 25.13, 22.85,14.27 ppm.

While various embodiments of the system, methods and devices have beendescribed above, it should be understood that they have been presentedby way of example only, and not limitation. Where methods and stepsdescribed above indicate certain events occurring in certain order,those of ordinary skill in the art having the benefit of this disclosurewould recognize that the ordering of certain steps may be modified andsuch modification are in accordance with the variations of theinvention. Additionally, certain of the steps may be performedconcurrently in a parallel process when possible, as well as performedsequentially as described above. The embodiments have been particularlyshown and described, but it will be understood that various changes inform and details may be made.

The invention claimed is:
 1. A method of forming a protective coating ona product, the product being pre-harvest and comprising a plant, aportion of a plant, or an agricultural product, the method comprising:obtaining a composition comprising monoacylglycerides, wherein themonoacylglycerides are formed by esterification of plant-derived fattyacids; causing the composition to be added to a solvent, thereby forminga mixture; and causing the mixture to be applied to a surface of theproduct to form the protective coating over the product, and wherein themethod further comprises causing the solvent to be removed from thesurface of the agricultural product.
 2. The method of claim 1, whereinthe product is a fruit, a vegetable, produce, a seed, a nut, or aflower.
 3. The method of claim 1, wherein the product is an edibleproduct.
 4. The method of claim 1, wherein the product is an inedibleproduct.
 5. The method of claim 1, wherein the protective coatingprevents diffusion of gaseous species.
 6. The method of claim 1, whereinthe fatty acids comprise at least one of hexadecanoic acid,16-hydroxyhexadecanoic acid, 9,16-dihydroxyhexadecanoic acid,10,16-dihydroxyhexadecanoic acid, or 9,10,16-trihydroxyhexadecanoicacid.
 7. The method of claim 1, wherein the fatty acids comprise atleast one of octadecanoic acid, 18-hydroxyoctadecanoic acid,9,18-dihydroxyoctadecanoic acid, 10,18-dihydroxyoctadecanoic acid, or9,10,18-trihydroxyoctadecanoic acid.
 8. A method of forming a protectivecoating on a product, the product being pre-harvest and comprising aplant, a portion of a plant, or an agricultural product, the methodcomprising: obtaining a composition comprising monoacylglycerides,wherein the monoacylglycerides are formed by transesterification ofplant-derived fatty acid esters; causing the composition to be added toa solvent, thereby forming a mixture; and causing the mixture to beapplied to a surface of the product to form a protective coating overthe product, and wherein the method further comprises causing thesolvent to be removed from the surface of the agricultural product. 9.The method of claim 8, wherein the product is a fruit, a vegetable,produce, a seed, a nut, or a flower.
 10. The method of claim 8, whereinthe protective coating prevents diffusion of gaseous species.
 11. Amethod of treating forming a protective coating on a product, theproduct being pre-harvest and comprising a plant, a portion of a plant,or an agricultural product, the method comprising: obtaining acomposition comprising monoacylglycerides, wherein themonoacylglycerides are formed by esterification of plant-derived fattyacids; and causing the composition to be applied to a surface of theproduct to form a protective coating over the product, wherein theobtaining of the composition comprises obtaining a mixture comprisingthe composition in a solvent, and wherein the method further comprisescausing the solvent to be removed from the surface of the agriculturalproduct.
 12. The method of claim 11, wherein the fatty acids comprise atleast one of hexadecanoic acid, 16-hydroxyhexadecanoic acid,9,16-dihydroxyhexadecanoic acid, 10,16-dihydroxyhexadecanoic acid,9,10,16-trihydroxyhexadecanoic acid, octadecanoic acid,18-hydroxyoctadecanoic acid, 9,18-dihydroxyoctadecanoic acid,10,18-dihydroxyoctadecanoic acid, or 9,10,18-trihydroxyoctadecanoicacid.
 13. The method of claim 11, wherein the product is a fruit, avegetable, produce, a seed, a nut, or a flower.
 14. A method of forminga protective coating on a product, the product being pre-harvest andcomprising a plant, a portion of a plant, or an agricultural product,the method comprising: obtaining a composition comprisingmonoacylglycerides, wherein the monoacylglycerides are formed bytransesterification of plant-derived fatty acids; and causing thecomposition to be applied to a surface of the product to form aprotective coating on the product, wherein the obtaining of thecomposition comprises obtaining a mixture comprising the composition ina solvent, and wherein the method further comprises causing the solventto be removed from the surface of the agricultural product.
 15. Themethod of claim 1, 8, 11 or 14 wherein the mixture further comprises anemulsifier.
 16. The method of claim 1, 8, 11 or 14, wherein the solventcomprises water or ethanol.
 17. The method of claim 8, 11 or 14, whereinthe monoacylglycerides are compounds of Formula I, wherein Formula I is:

wherein: R is a 1-glyceryl or a 2-glyceryl; R¹, R², R⁵, R⁶, R⁹, R¹⁰,R¹¹, R¹² and R¹³ are each independently —H, —OR¹⁴, —NR¹⁴R¹⁵, —SR¹⁴,halogen, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₂-C₆ alkynyl, —C₃-C₇cycloalkyl, —C₆-C₁₀ aryl, or 5 to 10-membered ring heteroaryl, whereineach —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₂-C₆ alkynyl, —C₃-C₇ cycloalkyl,—C₆-C₁₀ aryl, or 5 to 10-membered ring heteroaryl is optionallysubstituted with —OR¹⁴, —NR¹⁴R¹⁵, —SR¹⁴, or halogen; R³, R⁴, R⁷ and R⁸are each independently —H, —OR¹⁴, —NR¹⁴R¹⁵, —SR¹⁴, halogen, —C₁-C₆alkyl, —C₂-C₆ alkenyl, —C₂-C₆ alkynyl, —C₃-C₇ cycloalkyl, —C₆-C₁₀ aryl,or 5 to 10-membered ring heteroaryl wherein each —C₁-C₆ alkyl, —C₂-C₆alkenyl, —C₂-C₆ alkynyl, —C₃-C₇ cycloalkyl, —C₆-C₁₀ aryl, or 5 to10-membered ring heteroaryl is optionally substituted with —OR¹⁴,—NR¹⁴R¹⁵, —SR¹⁴, or halogen; or R³ and R⁴ are optionally combined withthe carbon atoms to which they are attached to form a 3 to 6-memberedring, such as a cyclic ether; R⁷ and R⁸ are optionally combined with thecarbon atoms to which they are attached to form a 3 to 6-membered ring,such as a cyclic ether; R¹⁴ and R¹⁵ are each independently —H, —C₁-C₆alkyl, —C₁-C₆ alkenyl, or —C₁-C₆ alkynyl; the symbol

represents an optionally single or cis or trans double bond; n is aninteger between 0 and 8; m is an integer between 0 and 3; q is aninteger between 0 and 5; and r is an integer between 0 and
 8. 18. Themethod of claim 1, 8, 11 or 14, wherein the composition furthercomprises a salt of a fatty acid.
 19. The method of claim 1, 8, 11 or14, wherein the mixture further comprises a weak acid.
 20. The method ofclaim 14, wherein the product is a fruit, a vegetable, produce, a seed,a nut, or a flower.
 21. The method of claim 14, wherein the protectivecoating prevents diffusion of gaseous species.
 22. The method of claim14, wherein the product is an edible product.
 23. The method of claim14, wherein the product is an inedible product.